{"id":797,"date":"2026-05-27T14:50:59","date_gmt":"2026-05-27T12:50:59","guid":{"rendered":"https:\/\/diamandmuseum-wordpress.caprover2.kavango.nl\/?page_id=797"},"modified":"2026-05-27T14:50:59","modified_gmt":"2026-05-27T12:50:59","slug":"the-4-cs","status":"publish","type":"page","link":"https:\/\/diamondmuseum.com\/nl\/the-4-cs\/","title":{"rendered":"De vier C's"},"content":{"rendered":"\n<div class=\"wp-block-group has-base-color has-accent-3-background-color has-text-color has-background has-link-color wp-elements-0275c1fe8ab1f5429d1398e13a232ee7 is-layout-flow wp-block-group-is-layout-flow\" style=\"min-height:5vh;padding-top:var(--wp--preset--spacing--30);padding-right:var(--wp--preset--spacing--30);padding-bottom:var(--wp--preset--spacing--30);padding-left:var(--wp--preset--spacing--30)\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<div class=\"wp-block-columns are-vertically-aligned-center is-not-stacked-on-mobile is-layout-flex wp-container-core-columns-is-layout-d9c913d5 wp-block-columns-is-layout-flex\" style=\"padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px\">\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-container-core-group-is-layout-fa08612f wp-block-group-is-layout-constrained\" style=\"padding-right:0;padding-left:0\">\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-ddf96df5 wp-block-group-is-layout-flex\"><nav style=\"font-size:12px;font-style:normal;font-weight:200\" class=\"is-responsive items-justified-left wp-block-navigation is-content-justification-left is-layout-flex wp-container-core-navigation-is-layout-49b994a3 wp-block-navigation-is-layout-flex\" aria-label=\"Navigation\" \n\t\t data-wp-interactive=\"core\/navigation\" data-wp-context='{\"overlayOpenedBy\":{\"click\":false,\"hover\":false,\"focus\":false},\"type\":\"overlay\",\"roleAttribute\":\"\",\"ariaLabel\":\"Menu\"}'><button aria-haspopup=\"dialog\" aria-label=\"Menu openen\" class=\"wp-block-navigation__responsive-container-open always-shown\" \n\t\t\t\tdata-wp-on--click=\"actions.openMenuOnClick\"\n\t\t\t\tdata-wp-on--keydown=\"actions.handleMenuKeydown\"\n\t\t\t><svg width=\"24\" height=\"24\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 24 24\"><path d=\"M5 5v1.5h14V5H5z\"><\/path><path d=\"M5 12.8h14v-1.5H5v1.5z\"><\/path><path d=\"M5 19h14v-1.5H5V19z\"><\/path><\/svg><\/button>\n\t\t\t\t<div class=\"wp-block-navigation__responsive-container hidden-by-default disable-default-overlay\"  id=\"modal-1\" \n\t\t\t\tdata-wp-class--has-modal-open=\"state.isMenuOpen\"\n\t\t\t\tdata-wp-class--is-menu-open=\"state.isMenuOpen\"\n\t\t\t\tdata-wp-watch=\"callbacks.initMenu\"\n\t\t\t\tdata-wp-on--keydown=\"actions.handleMenuKeydown\"\n\t\t\t\tdata-wp-on--focusout=\"actions.handleMenuFocusout\"\n\t\t\t\ttabindex=\"-1\"\n\t\t\t>\n\t\t\t\t\t<div class=\"wp-block-navigation__responsive-close\" tabindex=\"-1\">\n\t\t\t\t\t\t<div class=\"wp-block-navigation__responsive-dialog\" \n\t\t\t\tdata-wp-bind--aria-modal=\"state.ariaModal\"\n\t\t\t\tdata-wp-bind--aria-label=\"state.ariaLabel\"\n\t\t\t\tdata-wp-bind--role=\"state.roleAttribute\"\n\t\t\t>\n\t\t\t\t\t\t\t\n\t\t\t\t\t\t\t<div class=\"wp-block-navigation__responsive-container-content\" \n\t\t\t\tdata-wp-watch=\"callbacks.focusFirstElement\"\n\t\t\t id=\"modal-1-content\">\n\t\t\t\t\t\t\t\t<ul style=\"font-size:12px;font-style:normal;font-weight:200\" class=\"wp-block-navigation__container is-responsive items-justified-left wp-block-navigation\"><li style=\"font-size: 12px\" class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"\/contact\"><span class=\"wp-block-navigation-item__label\">Contact &amp; Visit<\/span><\/a><\/li><li style=\"font-size: 12px\" class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/tickets\/\"><span class=\"wp-block-navigation-item__label\">Tickets<\/span><\/a><\/li><li style=\"font-size: 12px\" class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/history\/\"><span class=\"wp-block-navigation-item__label\">History<\/span><\/a><\/li><li style=\"font-size: 12px\" class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/about-us\/\"><span class=\"wp-block-navigation-item__label\">About us<\/span><\/a><\/li><\/ul>\n\t\t\t\t\t\t\t\t<div class=\"wp-block-navigation__overlay-container\">\n<div class=\"wp-block-group has-base-color has-accent-3-background-color has-text-color has-background has-link-color is-layout-flow wp-block-group-is-layout-flow\" style=\"min-height:90vh;padding-top:var(--wp--preset--spacing--40);padding-right:var(--wp--preset--spacing--40);padding-bottom:var(--wp--preset--spacing--40);padding-left:var(--wp--preset--spacing--40)\">\n<div class=\"wp-block-group alignwide is-content-justification-right is-nowrap is-layout-flex wp-container-core-group-is-layout-6b33944b wp-block-group-is-layout-flex\"><button data-wp-on--click=\"actions.closeMenuOnClick\" class=\"wp-block-navigation-overlay-close\" type=\"button\" aria-label=\"Sluiten\" ><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 24 24\" width=\"24\" height=\"24\" aria-hidden=\"true\" focusable=\"false\"><path d=\"M13 11.8l6.1-6.3-1.1-1-6.1 6.2-6.1-6.2-1.1 1 6.1 6.3-6.5 6.7 1.1 1 6.5-6.6 6.5 6.6 1.1-1z\" \/><\/svg><\/button><\/div>\n\n\n<div class=\"is-vertical wp-block-navigation is-layout-flex wp-container-core-navigation-is-layout-7dd020c4 wp-block-navigation-is-layout-flex\" aria-label=\"Navigation\"><ul class=\"wp-block-navigation__container is-vertical wp-block-navigation\"><li class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"\/contact\"><span class=\"wp-block-navigation-item__label\">Contact &amp; Visit<\/span><\/a><\/li><li class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/tickets\/\"><span class=\"wp-block-navigation-item__label\">Tickets<\/span><\/a><\/li><li class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/history\/\"><span class=\"wp-block-navigation-item__label\">History<\/span><\/a><\/li><li class=\"wp-block-navigation-item wp-block-navigation-link\"><a class=\"wp-block-navigation-item__content\"  href=\"https:\/\/diamondmuseum.com\/nl\/about-us\/\"><span class=\"wp-block-navigation-item__label\">About us<\/span><\/a><\/li><\/ul><\/div>\n\n<div class=\"trp-block-container\"><div class=\"trp-shortcode-switcher__wrapper\"\r\n     style=\"--bg:#00263f00;--bg-hover:#ffffffb2;--text:#ffffff;--text-hover:#000000;--border:none;--border-width:0px;--border-color:transparent;--border-radius:3px;--flag-radius:2px;--flag-size:18px;--aspect-ratio:4\/3;--font-size:14px;--transition-duration:0.2s\"\r\n     role=\"group\"\r\n     data-open-mode=\"hover\">\r\n\r\n    \r\n        <!-- ANCHOR (in-flow only; sizing\/borders; inert) -->\r\n        <div class=\"trp-language-switcher trp-ls-dropdown trp-shortcode-switcher trp-shortcode-anchor trp-open-on-hover\"\r\n             aria-hidden=\"true\"\r\n             inert\r\n             data-no-translation>\r\n                <div class=\"trp-current-language-item__wrapper\">\r\n        <a class=\"trp-language-item trp-language-item__default trp-language-item__current\" data-no-translation href=\"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797#TRPLINKPROCESSED\" title=\"\"><img decoding=\"async\" fetchpriority=\"low\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/nl_NL.svg\" class=\"trp-flag-image\" alt=\"\" role=\"presentation\" loading=\"lazy\" \/><\/a>                    <svg class=\"trp-shortcode-arrow\" width=\"20\" height=\"20\" viewBox=\"0 0 20 21\" fill=\"none\" aria-hidden=\"true\" focusable=\"false\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\r\n                <path d=\"M5 8L10 13L15 8\" stroke=\"var(--text)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\/>\r\n            <\/svg>\r\n            <\/div>\r\n            <\/div>\r\n\r\n        <!-- OVERLAY (positioned; interactive surface) -->\r\n        <div class=\"trp-language-switcher trp-ls-dropdown trp-shortcode-switcher trp-shortcode-overlay trp-open-on-hover\"\r\n             role=\"navigation\"\r\n             aria-label=\"Site taalkiezer\"\r\n             data-no-translation\r\n        >\r\n                <div class=\"trp-current-language-item__wrapper\">\r\n        <div class=\"trp-language-item trp-language-item__default trp-language-item__current\" data-no-translation role=\"button\" aria-expanded=\"false\" tabindex=\"0\" aria-label=\"Taal wijzigen\" aria-controls=\"trp-shortcode-dropdown-6a3c75ae9a1f3\"><img decoding=\"async\" fetchpriority=\"low\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/nl_NL.svg\" class=\"trp-flag-image\" alt=\"\" role=\"presentation\" loading=\"lazy\" \/><\/div>                    <svg class=\"trp-shortcode-arrow\" width=\"20\" height=\"20\" viewBox=\"0 0 20 21\" fill=\"none\" aria-hidden=\"true\" focusable=\"false\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\r\n                <path d=\"M5 8L10 13L15 8\" stroke=\"var(--text)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\/>\r\n            <\/svg>\r\n            <\/div>\r\n    \r\n            <div class=\"trp-switcher-dropdown-list\"\r\n                 id=\"trp-shortcode-dropdown-6a3c75ae9a1f3\"\r\n                 role=\"group\"\r\n                 aria-label=\"Beschikbare talen\"\r\n                 hidden\r\n                 inert\r\n            >\r\n                                                            <a class=\"trp-language-item\" href=\"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797#TRPLINKPROCESSED\" title=\"\">\r\n                            <img decoding=\"async\" fetchpriority=\"low\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/en_US.svg\" class=\"trp-flag-image\" alt=\"Taal wijzigen naar English\" loading=\"lazy\" \/>                                                                                <\/a>\r\n                                                <\/div>\r\n        <\/div>\r\n\r\n    <\/div>\r\n<\/div><\/div>\n<\/div>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div><\/nav>\n\n\n<div class=\"wp-block-group kma-menu-hide has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"has-small-font-size wp-block-paragraph\"><a style=\"text-decoration:none;\" href=\"https:\/\/diamondmuseum.com\/about-us\/\" data-type=\"page\" data-id=\"145\">About<\/a><\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-group kma-menu-hide has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<p class=\"has-small-font-size wp-block-paragraph\"><a style=\"text-decoration:none;\" href=\"https:\/\/diamondmuseum.com\/history\/\" data-type=\"page\" data-id=\"219\">Heritage<\/a><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\" style=\"padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;flex-basis:40%\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\"><div style=\"margin-top:var(--wp--preset--spacing--20)\" class=\"aligncenter wp-block-site-logo\"><a href=\"https:\/\/diamondmuseum.com\/nl\/\" class=\"custom-logo-link\" rel=\"home\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"77\" src=\"https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/Group-54-v.png\" class=\"custom-logo\" alt=\"Diamond Museum\" srcset=\"https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/Group-54-v.png 582w, https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/Group-54-v-300x77.png 300w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><\/div><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-vertically-aligned-center is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<div class=\"wp-block-group has-medium-font-size is-content-justification-right is-nowrap is-layout-flex wp-container-core-group-is-layout-8468eae6 wp-block-group-is-layout-flex\">\n<div class=\"wp-block-group kma-deskmenu has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<div class=\"wp-block-group is-nowrap is-layout-flex wp-container-core-group-is-layout-ddf96df5 wp-block-group-is-layout-flex\">\n<a href=\"https:\/\/www.royalcoster.com\/en\" target=\"_blank\" rel=\"noopener\" style=\"text-decoration: none; color: white; font-size: 14px;\">\n  Store <i class=\"fa-regular fa-share-from-square\" style=\"font-size: 12px; margin-left: 2px;\"><\/i>\n<\/a>\n\n\n<div class=\"trp-block-container\"><div class=\"trp-shortcode-switcher__wrapper\"\r\n     style=\"--bg:#00263f00;--bg-hover:#ffffffb2;--text:#ffffff;--text-hover:#000000;--border:none;--border-width:0px;--border-color:transparent;--border-radius:3px;--flag-radius:2px;--flag-size:18px;--aspect-ratio:4\/3;--font-size:14px;--transition-duration:0.2s\"\r\n     role=\"group\"\r\n     data-open-mode=\"hover\">\r\n\r\n    \r\n        <!-- ANCHOR (in-flow only; sizing\/borders; inert) -->\r\n        <div class=\"trp-language-switcher trp-ls-dropdown trp-shortcode-switcher trp-shortcode-anchor trp-open-on-hover\"\r\n             aria-hidden=\"true\"\r\n             inert\r\n             data-no-translation>\r\n                <div class=\"trp-current-language-item__wrapper\">\r\n        <a class=\"trp-language-item trp-language-item__default trp-language-item__current\" data-no-translation href=\"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797#TRPLINKPROCESSED\" title=\"\"><img decoding=\"async\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/nl_NL.svg\" class=\"trp-flag-image\" alt=\"\" role=\"presentation\" loading=\"lazy\" \/><\/a>                    <svg class=\"trp-shortcode-arrow\" width=\"20\" height=\"20\" viewBox=\"0 0 20 21\" fill=\"none\" aria-hidden=\"true\" focusable=\"false\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\r\n                <path d=\"M5 8L10 13L15 8\" stroke=\"var(--text)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\/>\r\n            <\/svg>\r\n            <\/div>\r\n            <\/div>\r\n\r\n        <!-- OVERLAY (positioned; interactive surface) -->\r\n        <div class=\"trp-language-switcher trp-ls-dropdown trp-shortcode-switcher trp-shortcode-overlay trp-open-on-hover\"\r\n             role=\"navigation\"\r\n             aria-label=\"Site taalkiezer\"\r\n             data-no-translation\r\n        >\r\n                <div class=\"trp-current-language-item__wrapper\">\r\n        <div class=\"trp-language-item trp-language-item__default trp-language-item__current\" data-no-translation role=\"button\" aria-expanded=\"false\" tabindex=\"0\" aria-label=\"Taal wijzigen\" aria-controls=\"trp-shortcode-dropdown-6a3c75ae9bdc6\"><img decoding=\"async\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/nl_NL.svg\" class=\"trp-flag-image\" alt=\"\" role=\"presentation\" loading=\"lazy\" \/><\/div>                    <svg class=\"trp-shortcode-arrow\" width=\"20\" height=\"20\" viewBox=\"0 0 20 21\" fill=\"none\" aria-hidden=\"true\" focusable=\"false\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\r\n                <path d=\"M5 8L10 13L15 8\" stroke=\"var(--text)\" stroke-width=\"2\" stroke-linecap=\"round\" stroke-linejoin=\"round\"\/>\r\n            <\/svg>\r\n            <\/div>\r\n    \r\n            <div class=\"trp-switcher-dropdown-list\"\r\n                 id=\"trp-shortcode-dropdown-6a3c75ae9bdc6\"\r\n                 role=\"group\"\r\n                 aria-label=\"Beschikbare talen\"\r\n                 hidden\r\n                 inert\r\n            >\r\n                                                            <a class=\"trp-language-item\" href=\"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797#TRPLINKPROCESSED\" title=\"\">\r\n                            <img decoding=\"async\" src=\"https:\/\/diamondmuseum.com\/wp-content\/plugins\/translatepress-multilingual\/assets\/flags\/4x3\/en_US.svg\" class=\"trp-flag-image\" alt=\"Taal wijzigen naar English\" loading=\"lazy\" \/>                                                                                <\/a>\r\n                                                <\/div>\r\n        <\/div>\r\n\r\n    <\/div>\r\n<\/div><\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-group has-border-color has-global-padding is-layout-constrained wp-container-core-group-is-layout-68053202 wp-block-group-is-layout-constrained\" style=\"border-color:#FFFFFF;border-width:1px;border-top-left-radius:5px;border-top-right-radius:5px;border-bottom-left-radius:5px;border-bottom-right-radius:5px;padding-right:var(--wp--preset--spacing--30);padding-left:var(--wp--preset--spacing--30)\">\n<a href=\"https:\/\/fareharbor.com\/embeds\/book\/royalcosterdiamondbv\/?full-items=yes&amp;ref=DMA&amp;flow=1643424\" target=\"_blank\" onclick=\"FH.open({&#039;shortname&#039;:&#039;royalcosterdiamondbv&#039;,&#039;view&#039;:&#039;items&#039;,&#039;fallback&#039;:&#039;simple&#039;,&#039;fullItems&#039;:&#039;yes&#039;,&#039;ref&#039;:&#039;DMA&#039;,&#039;flow&#039;:&#039;1643424&#039;}); return false;\"><p style=\"font-size:small; text-decoration:none;\">Tickets<\/p><\/a>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-cover is-light\" style=\"margin-top:0;margin-bottom:0;padding-top:0;padding-bottom:0;min-height:250px;aspect-ratio:unset;\"><span aria-hidden=\"true\" class=\"wp-block-cover__background has-accent-1-background-color has-background-dim-100 has-background-dim\"><\/span><div class=\"wp-block-cover__inner-container has-global-padding is-layout-constrained wp-container-core-cover-is-layout-6e9e3788 wp-block-cover-is-layout-constrained\">\n<p class=\"has-text-align-left has-accent-3-color has-text-color has-link-color wp-elements-a9e45ed2b588c6569725ad2ccc4fb2a6 wp-block-paragraph\" style=\"font-size:clamp(23.043px, 1.44rem + ((1vw - 3.2px) * 1.466), 38px);font-style:normal;font-weight:500;letter-spacing:10%;line-height:1.1;text-transform:uppercase\">The 4 C&#8217;s<\/p>\n<\/div><\/div>\n\n\n\n<div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\" style=\"padding-right:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-container-core-group-is-layout-82df9d81 wp-block-group-is-layout-constrained\" style=\"border-style:none;border-width:0px;padding-top:0;padding-right:0;padding-bottom:0;padding-left:0\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-container-core-group-is-layout-99a96387 wp-block-group-is-layout-constrained\" style=\"border-width:1px;border-top-left-radius:10px;border-top-right-radius:10px;border-bottom-left-radius:10px;border-bottom-right-radius:10px;padding-top:var(--wp--preset--spacing--50);padding-right:var(--wp--preset--spacing--50);padding-bottom:var(--wp--preset--spacing--50);padding-left:var(--wp--preset--spacing--50)\">\n<p class=\"wp-block-paragraph\">The value of a diamond is determined by 4 quality factors. These were established in Amsterdam in 1975, during the congress of the World Federation of Diamond Bourses (W.F.D.B.) and the International Diamond Manufacturers Association (I.D.M.A.). It became known as the system of the 4 C&#8217;s, after the words Carat, Colour, Cut and Clarity. The larger the diamond and the finer the colour, the higher its value is; the greater the clarity, the more beautiful and better cut, the more perfect it is.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The price of diamonds is kept stable by regulating what flows into the market. The world stock is supposedly large enough to provide a cupful of diamonds for every inhabitant of the USA.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Carat<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">From time immemorial the seeds of the carob tree were used to determine the weight of gemstones on the scales. These seeds have a very stable weight of 0.2 grams. In Greek this kind of seed is called Keration (in Arabic, &#8220;Kharrub&#8221;). The word carat is derived from this. Another weighing measurement used in the diamond trade is the grain, that comes from the Latin word &#8220;granum&#8221; meaning &#8220;grain&#8221;. The more or less standard weight of a grain of corn is 0.05 grams. In 1907 it was internationally established that 1 carat is equal to 0.2 grams, and equal to 4 grains. For diamonds, 1 carat is further subdivided into 100 points. The word carat is also used to indicate the gold content in gold.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Rati<\/strong> \u2014 the seeds of the deadly Abrus Precatorius, were used for centuries to determine the weight of diamonds and other gemstones (1 rati = 0.2 gram).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Kernels of corn (grains)<\/strong> \u2014 were also used as standard units of measure for weighing pearls and gemstones (1 grain = 0.05 gram).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Seeds of the Carob tree<\/strong> \u2014 have almost the same weight as the red rati of the Abrus Precatorius and were also used to determine the weight of diamonds and other gemstones. The pod of the carob tree.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 Prior to setting the carat weight at 0.2 gram internationally in 1907, various different carat weights co-existed per region. In Bologna, 188.5 milligrams applied and in Vienna 206.1 milligrams. In 1871, traders from London, Paris and Amsterdam agreed that a carat equalled 0.205 gram. Later this became 0.2 gram. The legendary Great Mogul weighed 319 rati and 279.72 Florentine carats. In today&#8217;s carat that would have been 191.40. The diamond, which disappeared without a trace, could perhaps be the Pramaha Vichien Mani (the &#8216;Greatest of All Crystal&#8217;) that now sits on top of the Thai coronation crown.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Scales<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Sieves<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Sliding callipers<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Size fan<\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Clarity<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The crystallization of diamonds is a natural process in which other materials can be included and are often visible as black particles. Cracks or air bubbles can also be enclosed. These imperfections are called inclusions. The clarity of a diamond is determined with a loupe at 10\u00d7 magnification. Most diamonds contain flaws (inclusions) which came into being during the crystallisation process. A diamond free of inclusions is called internally flawless. Inclusions which can be observed with magnifying glass capable of ten times magnification decrease the value of the diamond.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>IF (Internally Flawless)<\/strong>&nbsp; No inclusions visible at tenfold magnification.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>SI (Small Inclusions)<\/strong>&nbsp; Small inclusions.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Piqu\u00e9<\/strong>&nbsp; Inclusions that can be seen with the naked eye.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Colour<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The more colourless the stone, the more valuable the diamond. Only a very small number of diamonds are completely colourless; most vary in very light hues from yellow to brown. Many other distinct colours also occur, the so-called fancy colours. Colour comes about as the result of chemical substances penetrating the atomic structure: these include nitrogen (yellow), magnesium (rose), radium (green) and borium (blue). Red is the rarest colour and therefore very costly.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The colour of diamonds can be changed artificially by irradiation with electrons. The artificial colouring must be mentioned in the certificate for these diamonds: &#8220;Artificially coloured by treatment&#8221;. The colour of a diamond is determined by comparing the stone with &#8220;master stones&#8221;. These are reference stones that correspond with the colour scale for diamonds established by international professional organisations in 1978. The fancy colours fall outside this framework.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Master stones<\/strong>&nbsp; For colour comparison: the reference set against which a diamond&#8217;s colour is determined.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Collier of the Maharaja of Nawanagar<\/strong>&nbsp; The central diamond, of 135.92 carats, in this state necklace that once belonged to the Maharaja of Nawanagar, is the Queen of Holland. It was given this name in honour of the 25-year jubilee of Queen Wilhelmina in 1923. In addition, rose, green, blue and white diamonds are incorporated in the necklace. Cartier, who created the necklace, described it as &#8220;the truly superb achievement of a connoisseur&#8217;s dream&#8221; (replica).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Star-shaped aigrette with the Hancock Red<\/strong>&nbsp; The star-shaped aigrette that adorns the Tengolok of Sultan Hassanal Bolkiah of Brunei is set with the most expensive red diamond, the Hancock Red, and a number of yellow and pink diamonds (replica).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Cognac on Ice, 34 carats<\/strong>&nbsp; For a long time, brown diamonds were the least valued. The Cognac on Ice, of 34 carats, is famous despite the fact that it is brown. It was purchased in 1974 by Richard Burton, who gave it to his wife Elizabeth Taylor (replica).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Fancy Vivid Brown, Royal Cut Diamond<\/strong>&nbsp; 0.78 ct, natural colour, VS1, Royal Cut. Set in a rose gold ring, combined with white diamonds. This stone \u2014 special both in colour and shape \u2014 was polished by Mr R. Neefs from Turnhout, Belgium and donated to the Diamond Museum in 2022.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Cut<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In the past centuries, different types of cuts have come into existence, partly as a consequence of technological progress. Before 1400 the given crystal shape was used, such as the octahedron \u2014 two pyramids with their bases together. Later, the better-reflecting table-shaped cut came into fashion. At the end of the 15th century, the Antwerp polisher Lodewijk van Berken invented the revolutionary polishing scaife. As a result of this it became possible to cut symmetrical facets. Thus, in the 16th century the rose cut, with a limited number of facets, came into vogue in Europe. In the 17th century, diamonds were for the first time cut in brilliant shape with its many facets. Depending on its proportions, the round brilliant with 57 facets is the ideal cut.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Diamond projector<\/strong>&nbsp; The proportion meter, also called a diamond projector, is an instrument to control the exact proportions of diamonds in brilliant cut. Various screens are used for different sizes and different standards, the American and the European standard.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u2022 <strong>Cut shapes: Emerald, Princess, Brilliant, Triangle, Marquise<\/strong>&nbsp; Specimens of well-known diamond cuts.<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div style=\"height:150px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-group kma-footer is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-group has-accent-3-background-color has-background has-global-padding is-layout-constrained wp-container-core-group-is-layout-71f64726 wp-block-group-is-layout-constrained\" style=\"padding-top:var(--wp--preset--spacing--50);padding-right:var(--wp--preset--spacing--20);padding-bottom:var(--wp--preset--spacing--50);padding-left:var(--wp--preset--spacing--20)\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><a href=\"\/\"><img loading=\"lazy\" decoding=\"async\" width=\"205\" height=\"117\" src=\"https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/DMA_logo_PMS424C-copy-1.png\" alt=\"\" class=\"wp-image-101\" style=\"width:120px\"\/><\/a><\/figure>\n<\/div>\n\n\n\n<div style=\"height:60px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-794e3cfa wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:60%\">\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-large-font-size wp-elements-53247d2ffd7c558c443c36c3b838f610 wp-block-paragraph\"><strong>Visitor information<\/strong><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-medium-font-size wp-elements-ced2cb2f1764c1993f55c4d12ec3105b wp-block-paragraph\">Open daily 9 to 17h<\/p>\n\n\n\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-f0daa8b0c83d299847537aaf9e789100 wp-block-paragraph\">Paulus Potterstraat 6, Amsterdam <\/p>\n\n\n\n<div style=\"height:5px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-9d8f87e8b4e4d9680a888ffd27e5bb9d wp-block-paragraph\">Entrance at Paulus Potterstraat 2<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-container-core-column-is-layout-470551b9 wp-block-column-is-layout-flow\" style=\"flex-basis:20%\">\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-large-font-size wp-elements-4040c4fba13fd2e05d7d805c64604d8e wp-block-paragraph\"><strong>Links<\/strong><\/p>\n\n\n\n<div style=\"height:20px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-0a0c1622807513e6188f77ed6f684957 wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/tickets\/\" data-type=\"page\" data-id=\"348\">Tickets<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-57268a57f09252f2da3c42e8ddfbf5ce wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/about-us\/\">About<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-23a1b592744b0e00ae17eb84fc9984ab wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/history\/\" data-type=\"page\" data-id=\"219\">History<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-27a3de43f1e21d0fe745f5467f7dfae0 wp-block-paragraph\"><a href=\"https:\/\/www.royalcoster.com\/en\" target=\"_blank\" rel=\"noreferrer noopener\">Store<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-6424fed338cbf927e573a318ba001583 wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/mission\/\" type=\"page\" id=\"617\">Mission<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-7dbdc38236f45492c609f313e85ee2a4 wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/faq\/\" type=\"page\" id=\"858\">FAQ<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-8c20d3ce7131d17aeda2a02e9b693eb5 wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/privacy-policy\/\" type=\"page\" id=\"655\">Privacy Policy<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-2edf57446a883c0764256daa966e760a wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/anbi-information\/\" type=\"page\" id=\"626\">ANBI information<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-4f67b3cb6ab2cb7607ade3efb407fe2b wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/trade-and-distribution\/\" type=\"page\" id=\"801\">Trade and Distribution<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-f2d3caf0e62b9f8ec9422112c440a7b4 wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/contact\/\" data-type=\"page\" data-id=\"288\">Contact<\/a><\/p>\n\n\n\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-small-font-size wp-elements-2deadddfcfc2f094b7d47015f9877d65 wp-block-hidden-desktop wp-block-hidden-mobile wp-block-hidden-tablet wp-block-paragraph\"><a href=\"https:\/\/diamondmuseum.com\/tour\/\" type=\"page\" id=\"650\">Tour<\/a><\/p>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:20%\">\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-large-font-size wp-elements-55c52b3e23e59a2e91bb729d08a1e1be wp-block-paragraph\"><strong>Follow us on socials<\/strong><\/p>\n\n\n\n<div style=\"height:var(--wp--preset--spacing--40)\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<a href=\"https:\/\/www.instagram.com\/diamondmuseum\/\" target=\"_blank\" rel=\"noopener\" style=\"text-decoration: none; color: white;\">\n  <i class=\"fa-brands fa-instagram\" style=\"font-size: 18px; \"><\/i>\n<\/a>\n\n\n\n<a href=\"https:\/\/www.facebook.com\/diamondmuseumroyalcoster\/\" target=\"_blank\" rel=\"noopener\" style=\"text-decoration: none; color: white;\">\n  <i class=\"fa-brands fa-square-facebook\" style=\"font-size: 18px; margin-left: 2px;\"><\/i>\n<\/a>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-group has-base-color has-accent-3-background-color has-text-color has-background has-link-color wp-elements-1294c4c7c44873756626690b30e30dff has-global-padding is-layout-constrained wp-container-core-group-is-layout-7667b874 wp-block-group-is-layout-constrained\" style=\"padding-top:0;padding-right:0;padding-bottom:0;padding-left:0\">\n<p class=\"has-text-align-left has-base-color has-text-color has-link-color has-large-font-size wp-elements-b9ff8c46ff856725935f41ac40a4895b wp-block-paragraph\" style=\"padding-bottom:var(--wp--preset--spacing--20)\">Don\u2019t miss a thing<\/p>\n\n\n\n<p class=\"has-base-color has-text-color has-link-color has-small-font-size wp-elements-20498ed96c9844bacd8ccf2a3e8d8fb4 wp-block-paragraph\">Keep up to date with our exhibitions and news<\/p>\n\n\n\n<div style=\"height:var(--wp--preset--spacing--40)\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div style=\"height:var(--wp--preset--spacing--40)\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div style=\"height:10px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div style=\"height:10px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<p class=\"has-accent-1-color has-text-color has-link-color has-small-font-size wp-elements-5c98f882c4cd6473f3ad92bf79a65be4 wp-block-paragraph\" style=\"font-style:normal;font-weight:600\">Subscribe<\/p>\n\n\n\n<div style=\"height:10px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n<script>\nvar gform;gform||(document.addEventListener(\"gform_main_scripts_loaded\",function(){gform.scriptsLoaded=!0}),document.addEventListener(\"gform\/theme\/scripts_loaded\",function(){gform.themeScriptsLoaded=!0}),window.addEventListener(\"DOMContentLoaded\",function(){gform.domLoaded=!0}),gform={domLoaded:!1,scriptsLoaded:!1,themeScriptsLoaded:!1,isFormEditor:()=>\"function\"==typeof InitializeEditor,callIfLoaded:function(o){return!(!gform.domLoaded||!gform.scriptsLoaded||!gform.themeScriptsLoaded&&!gform.isFormEditor()||(gform.isFormEditor()&&console.warn(\"The use of gform.initializeOnLoaded() is deprecated in the form editor context and will be removed in Gravity Forms 3.1.\"),o(),0))},initializeOnLoaded:function(o){gform.callIfLoaded(o)||(document.addEventListener(\"gform_main_scripts_loaded\",()=>{gform.scriptsLoaded=!0,gform.callIfLoaded(o)}),document.addEventListener(\"gform\/theme\/scripts_loaded\",()=>{gform.themeScriptsLoaded=!0,gform.callIfLoaded(o)}),window.addEventListener(\"DOMContentLoaded\",()=>{gform.domLoaded=!0,gform.callIfLoaded(o)}))},hooks:{action:{},filter:{}},addAction:function(o,r,e,t){gform.addHook(\"action\",o,r,e,t)},addFilter:function(o,r,e,t){gform.addHook(\"filter\",o,r,e,t)},doAction:function(o){gform.doHook(\"action\",o,arguments)},applyFilters:function(o){return gform.doHook(\"filter\",o,arguments)},removeAction:function(o,r){gform.removeHook(\"action\",o,r)},removeFilter:function(o,r,e){gform.removeHook(\"filter\",o,r,e)},addHook:function(o,r,e,t,n){null==gform.hooks[o][r]&&(gform.hooks[o][r]=[]);var d=gform.hooks[o][r];null==n&&(n=r+\"_\"+d.length),gform.hooks[o][r].push({tag:n,callable:e,priority:t=null==t?10:t})},doHook:function(r,o,e){var t;if(e=Array.prototype.slice.call(e,1),null!=gform.hooks[r][o]&&((o=gform.hooks[r][o]).sort(function(o,r){return o.priority-r.priority}),o.forEach(function(o){\"function\"!=typeof(t=o.callable)&&(t=window[t]),\"action\"==r?t.apply(null,e):e[0]=t.apply(null,e)})),\"filter\"==r)return e[0]},removeHook:function(o,r,t,n){var e;null!=gform.hooks[o][r]&&(e=(e=gform.hooks[o][r]).filter(function(o,r,e){return!!(null!=n&&n!=o.tag||null!=t&&t!=o.priority)}),gform.hooks[o][r]=e)}});\n<\/script>\n\n                <div class='gf_browser_gecko gform_wrapper gform-theme gform-theme--foundation gform-theme--framework gform-theme--orbital' data-form-theme='orbital' data-form-index='0' id='gform_wrapper_3' style='display:none'><style>#gform_wrapper_3[data-form-index=\"0\"].gform-theme,[data-parent-form=\"3_0\"]{--gf-color-primary: #204ce5;--gf-color-primary-rgb: 32, 76, 229;--gf-color-primary-contrast: #fff;--gf-color-primary-contrast-rgb: 255, 255, 255;--gf-color-primary-darker: #001AB3;--gf-color-primary-lighter: #527EFF;--gf-color-secondary: #fff;--gf-color-secondary-rgb: 255, 255, 255;--gf-color-secondary-contrast: #112337;--gf-color-secondary-contrast-rgb: 17, 35, 55;--gf-color-secondary-darker: #F5F5F5;--gf-color-secondary-lighter: #FFFFFF;--gf-color-out-ctrl-light: rgba(17, 35, 55, 0.1);--gf-color-out-ctrl-light-rgb: 17, 35, 55;--gf-color-out-ctrl-light-darker: rgba(104, 110, 119, 0.35);--gf-color-out-ctrl-light-lighter: #F5F5F5;--gf-color-out-ctrl-dark: #585e6a;--gf-color-out-ctrl-dark-rgb: 88, 94, 106;--gf-color-out-ctrl-dark-darker: #112337;--gf-color-out-ctrl-dark-lighter: rgba(17, 35, 55, 0.65);--gf-color-in-ctrl: #fff;--gf-color-in-ctrl-rgb: 255, 255, 255;--gf-color-in-ctrl-contrast: #112337;--gf-color-in-ctrl-contrast-rgb: 17, 35, 55;--gf-color-in-ctrl-darker: #F5F5F5;--gf-color-in-ctrl-lighter: #FFFFFF;--gf-color-in-ctrl-primary: #204ce5;--gf-color-in-ctrl-primary-rgb: 32, 76, 229;--gf-color-in-ctrl-primary-contrast: #fff;--gf-color-in-ctrl-primary-contrast-rgb: 255, 255, 255;--gf-color-in-ctrl-primary-darker: #001AB3;--gf-color-in-ctrl-primary-lighter: #527EFF;--gf-color-in-ctrl-light: rgba(17, 35, 55, 0.1);--gf-color-in-ctrl-light-rgb: 17, 35, 55;--gf-color-in-ctrl-light-darker: rgba(104, 110, 119, 0.35);--gf-color-in-ctrl-light-lighter: #F5F5F5;--gf-color-in-ctrl-dark: #585e6a;--gf-color-in-ctrl-dark-rgb: 88, 94, 106;--gf-color-in-ctrl-dark-darker: #112337;--gf-color-in-ctrl-dark-lighter: rgba(17, 35, 55, 0.65);--gf-radius: 3px;--gf-font-size-secondary: 14px;--gf-font-size-tertiary: 13px;--gf-icon-ctrl-number: url(\"data:image\/svg+xml,%3Csvg width='8' height='14' viewBox='0 0 8 14' fill='none' xmlns='http:\/\/www.w3.org\/2000\/svg'%3E%3Cpath fill-rule='evenodd' clip-rule='evenodd' d='M4 0C4.26522 5.96046e-08 4.51957 0.105357 4.70711 0.292893L7.70711 3.29289C8.09763 3.68342 8.09763 4.31658 7.70711 4.70711C7.31658 5.09763 6.68342 5.09763 6.29289 4.70711L4 2.41421L1.70711 4.70711C1.31658 5.09763 0.683417 5.09763 0.292893 4.70711C-0.0976311 4.31658 -0.097631 3.68342 0.292893 3.29289L3.29289 0.292893C3.48043 0.105357 3.73478 0 4 0ZM0.292893 9.29289C0.683417 8.90237 1.31658 8.90237 1.70711 9.29289L4 11.5858L6.29289 9.29289C6.68342 8.90237 7.31658 8.90237 7.70711 9.29289C8.09763 9.68342 8.09763 10.3166 7.70711 10.7071L4.70711 13.7071C4.31658 14.0976 3.68342 14.0976 3.29289 13.7071L0.292893 10.7071C-0.0976311 10.3166 -0.0976311 9.68342 0.292893 9.29289Z' fill='rgba(17, 35, 55, 0.65)'\/%3E%3C\/svg%3E\");--gf-icon-ctrl-select: url(\"data:image\/svg+xml,%3Csvg width='10' height='6' viewBox='0 0 10 6' fill='none' xmlns='http:\/\/www.w3.org\/2000\/svg'%3E%3Cpath fill-rule='evenodd' clip-rule='evenodd' d='M0.292893 0.292893C0.683417 -0.097631 1.31658 -0.097631 1.70711 0.292893L5 3.58579L8.29289 0.292893C8.68342 -0.0976311 9.31658 -0.0976311 9.70711 0.292893C10.0976 0.683417 10.0976 1.31658 9.70711 1.70711L5.70711 5.70711C5.31658 6.09763 4.68342 6.09763 4.29289 5.70711L0.292893 1.70711C-0.0976311 1.31658 -0.0976311 0.683418 0.292893 0.292893Z' fill='rgba(17, 35, 55, 0.65)'\/%3E%3C\/svg%3E\");--gf-icon-ctrl-search: url(\"data:image\/svg+xml,%3Csvg width='640' height='640' xmlns='http:\/\/www.w3.org\/2000\/svg'%3E%3Cpath d='M256 128c-70.692 0-128 57.308-128 128 0 70.691 57.308 128 128 128 70.691 0 128-57.309 128-128 0-70.692-57.309-128-128-128zM64 256c0-106.039 85.961-192 192-192s192 85.961 192 192c0 41.466-13.146 79.863-35.498 111.248l154.125 154.125c12.496 12.496 12.496 32.758 0 45.254s-32.758 12.496-45.254 0L367.248 412.502C335.862 434.854 297.467 448 256 448c-106.039 0-192-85.962-192-192z' fill='rgba(17, 35, 55, 0.65)'\/%3E%3C\/svg%3E\");--gf-label-space-y-secondary: var(--gf-label-space-y-md-secondary);--gf-ctrl-border-color: #686e77;--gf-ctrl-size: var(--gf-ctrl-size-md);--gf-ctrl-label-color-primary: #112337;--gf-ctrl-label-color-secondary: #112337;--gf-ctrl-choice-size: var(--gf-ctrl-choice-size-md);--gf-ctrl-checkbox-check-size: var(--gf-ctrl-checkbox-check-size-md);--gf-ctrl-radio-check-size: var(--gf-ctrl-radio-check-size-md);--gf-ctrl-btn-font-size: var(--gf-ctrl-btn-font-size-md);--gf-ctrl-btn-padding-x: var(--gf-ctrl-btn-padding-x-md);--gf-ctrl-btn-size: var(--gf-ctrl-btn-size-md);--gf-ctrl-btn-border-color-secondary: #686e77;--gf-ctrl-file-btn-bg-color-hover: #EBEBEB;--gf-field-img-choice-size: var(--gf-field-img-choice-size-md);--gf-field-img-choice-card-space: var(--gf-field-img-choice-card-space-md);--gf-field-img-choice-check-ind-size: var(--gf-field-img-choice-check-ind-size-md);--gf-field-img-choice-check-ind-icon-size: var(--gf-field-img-choice-check-ind-icon-size-md);--gf-field-pg-steps-number-color: rgba(17, 35, 55, 0.8);}<\/style><form method='post' enctype='multipart\/form-data'  id='gform_3'  action='\/nl\/wp-json\/wp\/v2\/pages\/797' data-formid='3' novalidate>\n                        <div class='gform-body gform_body'><div id='gform_fields_3' class='gform_fields top_label form_sublabel_below description_below validation_below'><div id=\"field_3_1\" class=\"gfield gfield--type-email gfield--input-type-email gfield--width-full field_sublabel_below gfield--no-description field_description_below hidden_label field_validation_below gfield_visibility_visible\"  ><label class='gfield_label gform-field-label' for='input_3_1'>Email<\/label><div class='ginput_container ginput_container_email'>\n                            <input name='input_1' id='input_3_1' type='email' value='' class='medium'   placeholder='Email address'  aria-invalid=\"false\"  \/>\n                        <\/div><\/div><\/div><\/div>\n        <div class='gform-footer gform_footer top_label'> <input type='submit' id='gform_submit_button_3' class='gform_button button' onclick='gform.submission.handleButtonClick(this);' data-submission-type='submit' value='Submit'  \/> \n            <input type='hidden' class='gform_hidden' name='gform_submission_method' data-js='gform_submission_method_3' value='postback' \/>\n            <input type='hidden' class='gform_hidden' name='gform_theme' data-js='gform_theme_3' id='gform_theme_3' value='orbital' \/>\n            <input type='hidden' class='gform_hidden' name='gform_style_settings' data-js='gform_style_settings_3' id='gform_style_settings_3' value='{&quot;inputPrimaryColor&quot;:&quot;#204ce5&quot;}' \/>\n            <input type='hidden' class='gform_hidden' name='is_submit_3' value='1' \/>\n            <input type='hidden' class='gform_hidden' name='gform_submit' value='3' \/>\n            \n            <input type='hidden' class='gform_hidden' name='gform_currency' data-currency='EUR' value='OXqXk7GRUik4stwitdK18BfG9EGeCn2qZYaXzUnJ7QVcOIqGcjD5sxt+u020RhAoRhorffQahOXIfp5lRaAZ2lSw3OP27JBDj5p3FcncWlSiPqs=' \/>\n            <input type='hidden' class='gform_hidden' name='gform_unique_id' value='' \/>\n            <input type='hidden' class='gform_hidden' name='state_3' value='WyJbXSIsIjYyZDRlM2EzODkzYWFlOWYyY2M4ODU2YzkxMjlmOWZjIl0=' \/>\n            <input type='hidden' autocomplete='off' class='gform_hidden' name='gform_target_page_number_3' id='gform_target_page_number_3' value='0' \/>\n            <input type='hidden' autocomplete='off' class='gform_hidden' name='gform_source_page_number_3' id='gform_source_page_number_3' value='1' \/>\n            <input type='hidden' name='gform_field_values' value='' \/>\n            \n        <\/div>\n                        <\/form>\n                        <\/div><script>\ngform.initializeOnLoaded( function() {gformInitSpinner( 3, 'https:\/\/diamondmuseum.com\/wp-content\/plugins\/gravityforms\/images\/spinner.svg', false );jQuery('#gform_ajax_frame_3').on('load',function(){var contents = jQuery(this).contents().find('*').html();var is_postback = contents.indexOf('GF_AJAX_POSTBACK') >= 0;if(!is_postback){return;}var form_content = jQuery(this).contents().find('#gform_wrapper_3');var is_confirmation = jQuery(this).contents().find('#gform_confirmation_wrapper_3').length > 0;var is_redirect = contents.indexOf('gformRedirect(){') >= 0;var is_form = form_content.length > 0 && ! is_redirect && ! is_confirmation;var mt = parseInt(jQuery('html').css('margin-top'), 10) + parseInt(jQuery('body').css('margin-top'), 10) + 100;if(is_form){form_content.find('form').css('opacity', 0);jQuery('#gform_wrapper_3').html(form_content.html());if(form_content.hasClass('gform_validation_error')){jQuery('#gform_wrapper_3').addClass('gform_validation_error');} else {jQuery('#gform_wrapper_3').removeClass('gform_validation_error');}setTimeout( function() { \/* delay the scroll by 50 milliseconds to fix a bug in chrome *\/  }, 50 );if(window['gformInitDatepicker']) {gformInitDatepicker();}if(window['gformInitPriceFields']) {gformInitPriceFields();}var current_page = jQuery('#gform_source_page_number_3').val();gformInitSpinner( 3, 'https:\/\/diamondmuseum.com\/wp-content\/plugins\/gravityforms\/images\/spinner.svg', false );jQuery(document).trigger('gform_page_loaded', [3, current_page]);window['gf_submitting_3'] = false;}else if(!is_redirect){var confirmation_content = jQuery(this).contents().find('.GF_AJAX_POSTBACK').html();if(!confirmation_content){confirmation_content = contents;}jQuery('#gform_wrapper_3').replaceWith(confirmation_content);jQuery(document).trigger('gform_confirmation_loaded', [3]);window['gf_submitting_3'] = false;wp.a11y.speak(jQuery('#gform_confirmation_message_3').text());}else{jQuery('#gform_3').append(contents);if(window['gformRedirect']) {gformRedirect();}}jQuery(document).trigger(\"gform_pre_post_render\", [{ formId: \"3\", currentPage: \"current_page\", abort: function() { this.preventDefault(); } }]);        if (event && event.defaultPrevented) {                return;        }        const gformWrapperDiv = document.getElementById( \"gform_wrapper_3\" );        if ( gformWrapperDiv ) {            const visibilitySpan = document.createElement( \"span\" );            visibilitySpan.id = \"gform_visibility_test_3\";            gformWrapperDiv.insertAdjacentElement( \"afterend\", visibilitySpan );        }        const visibilityTestDiv = document.getElementById( \"gform_visibility_test_3\" );        let postRenderFired = false;        function triggerPostRender() {            if ( postRenderFired ) {                return;            }            postRenderFired = true;            gform.core.triggerPostRenderEvents( 3, current_page );            if ( visibilityTestDiv ) {                visibilityTestDiv.parentNode.removeChild( visibilityTestDiv );            }        }        function debounce( func, wait, immediate ) {            var timeout;            return function() {                var context = this, args = arguments;                var later = function() {                    timeout = null;                    if ( !immediate ) func.apply( context, args );                };                var callNow = immediate && !timeout;                clearTimeout( timeout );                timeout = setTimeout( later, wait );                if ( callNow ) func.apply( context, args );            };        }        const debouncedTriggerPostRender = debounce( function() {            triggerPostRender();        }, 200 );        if ( visibilityTestDiv && visibilityTestDiv.offsetParent === null ) {            const observer = new MutationObserver( ( mutations ) => {                mutations.forEach( ( mutation ) => {                    if ( mutation.type === 'attributes' && visibilityTestDiv.offsetParent !== null ) {                        debouncedTriggerPostRender();                        observer.disconnect();                    }                });            });            observer.observe( document.body, {                attributes: true,                childList: false,                subtree: true,                attributeFilter: [ 'style', 'class' ],            });        } else {            triggerPostRender();        }    } );} );\n<\/script>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n\n\n\n<div class=\"wp-block-group has-accent-1-color has-contrast-background-color has-text-color has-background has-link-color has-small-font-size wp-elements-6307ccba977c6f7a1c5586732b801c09 has-global-padding is-layout-constrained wp-container-core-group-is-layout-77bede8f wp-block-group-is-layout-constrained\" style=\"padding-right:var(--wp--preset--spacing--20);padding-left:var(--wp--preset--spacing--20)\">\n<div class=\"wp-block-group has-global-padding is-layout-constrained wp-block-group-is-layout-constrained\">\n<div class=\"wp-block-group is-content-justification-space-between is-nowrap is-layout-flex wp-container-core-group-is-layout-bb1abd1a wp-block-group-is-layout-flex\" style=\"padding-top:var(--wp--preset--spacing--20);padding-right:0;padding-bottom:var(--wp--preset--spacing--20);padding-left:0\">\n<p class=\"has-text-align-right wp-block-paragraph\">\u00a9&nbsp; 2026 Diamond Museum<\/p>\n\n\n\n<p class=\"has-text-align-right wp-block-paragraph\">Website by <a href=\"https:\/\/kavango.nl\" data-type=\"link\" data-id=\"https:\/\/kavango.nl\" target=\"_blank\" rel=\"noreferrer noopener\">Kavango<\/a><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>The value of a diamond is determined by 4 quality factors. These were established in Amsterdam in 1975, during the congress of the World Federation of Diamond Bourses (W.F.D.B.) and the International Diamond Manufacturers Association (I.D.M.A.). It became known as the system of the 4 C&#8217;s, after the words Carat, Colour, Cut and Clarity. The [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"kma-clean","meta":{"footnotes":""},"class_list":["post-797","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>The 4 C&#039;s - Diamond Museum<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/diamondmuseum.com\/nl\/the-4-cs\/\" \/>\n<meta property=\"og:locale\" content=\"nl_NL\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"The 4 C&#039;s - Diamond Museum\" \/>\n<meta property=\"og:description\" content=\"The value of a diamond is determined by 4 quality factors. These were established in Amsterdam in 1975, during the congress of the World Federation of Diamond Bourses (W.F.D.B.) and the International Diamond Manufacturers Association (I.D.M.A.). It became known as the system of the 4 C&#8217;s, after the words Carat, Colour, Cut and Clarity. The [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/diamondmuseum.com\/nl\/the-4-cs\/\" \/>\n<meta property=\"og:site_name\" content=\"Diamond Museum\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Geschatte leestijd\" \/>\n\t<meta name=\"twitter:data1\" content=\"5 minuten\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/the-4-cs\\\/\",\"url\":\"https:\\\/\\\/diamondmuseum.com\\\/the-4-cs\\\/\",\"name\":\"The 4 C's - Diamond Museum\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#website\"},\"datePublished\":\"2026-05-27T12:50:59+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/the-4-cs\\\/#breadcrumb\"},\"inLanguage\":\"nl-NL\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/diamondmuseum.com\\\/the-4-cs\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/the-4-cs\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/diamondmuseum.com\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"The 4 C&#8217;s\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#website\",\"url\":\"https:\\\/\\\/diamondmuseum.com\\\/\",\"name\":\"Diamond Museum\",\"description\":\"\",\"publisher\":{\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/diamondmuseum.com\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"nl-NL\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#organization\",\"name\":\"Diamond Museum\",\"url\":\"https:\\\/\\\/diamondmuseum.com\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"nl-NL\",\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/diamondmuseum.com\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/logooo.png\",\"contentUrl\":\"https:\\\/\\\/diamondmuseum.com\\\/wp-content\\\/uploads\\\/2026\\\/04\\\/logooo.png\",\"width\":194,\"height\":50,\"caption\":\"Diamond Museum\"},\"image\":{\"@id\":\"https:\\\/\\\/diamondmuseum.com\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/www.instagram.com\\\/diamondmuseum\\\/\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"De 4 C's - Diamant Museum","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/diamondmuseum.com\/nl\/the-4-cs\/","og_locale":"nl_NL","og_type":"article","og_title":"The 4 C's - Diamond Museum","og_description":"The value of a diamond is determined by 4 quality factors. These were established in Amsterdam in 1975, during the congress of the World Federation of Diamond Bourses (W.F.D.B.) and the International Diamond Manufacturers Association (I.D.M.A.). It became known as the system of the 4 C&#8217;s, after the words Carat, Colour, Cut and Clarity. The [&hellip;]","og_url":"https:\/\/diamondmuseum.com\/nl\/the-4-cs\/","og_site_name":"Diamond Museum","twitter_card":"summary_large_image","twitter_misc":{"Geschatte leestijd":"5 minuten"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/diamondmuseum.com\/the-4-cs\/","url":"https:\/\/diamondmuseum.com\/the-4-cs\/","name":"De 4 C's - Diamant Museum","isPartOf":{"@id":"https:\/\/diamondmuseum.com\/#website"},"datePublished":"2026-05-27T12:50:59+00:00","breadcrumb":{"@id":"https:\/\/diamondmuseum.com\/the-4-cs\/#breadcrumb"},"inLanguage":"nl-NL","potentialAction":[{"@type":"ReadAction","target":["https:\/\/diamondmuseum.com\/the-4-cs\/"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/diamondmuseum.com\/the-4-cs\/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/diamondmuseum.com\/"},{"@type":"ListItem","position":2,"name":"The 4 C&#8217;s"}]},{"@type":"WebSite","@id":"https:\/\/diamondmuseum.com\/#website","url":"https:\/\/diamondmuseum.com\/","name":"Diamant Museum","description":"","publisher":{"@id":"https:\/\/diamondmuseum.com\/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/diamondmuseum.com\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"nl-NL"},{"@type":"Organization","@id":"https:\/\/diamondmuseum.com\/#organization","name":"Diamant Museum","url":"https:\/\/diamondmuseum.com\/","logo":{"@type":"ImageObject","inLanguage":"nl-NL","@id":"https:\/\/diamondmuseum.com\/#\/schema\/logo\/image\/","url":"https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/logooo.png","contentUrl":"https:\/\/diamondmuseum.com\/wp-content\/uploads\/2026\/04\/logooo.png","width":194,"height":50,"caption":"Diamond Museum"},"image":{"@id":"https:\/\/diamondmuseum.com\/#\/schema\/logo\/image\/"},"sameAs":["https:\/\/www.instagram.com\/diamondmuseum\/"]}]}},"_links":{"self":[{"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/comments?post=797"}],"version-history":[{"count":1,"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797\/revisions"}],"predecessor-version":[{"id":798,"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/pages\/797\/revisions\/798"}],"wp:attachment":[{"href":"https:\/\/diamondmuseum.com\/nl\/wp-json\/wp\/v2\/media?parent=797"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}