April’s birthstone is diamond and many people are surprised to know that diamonds can come in virtually all colours of the rainbow. This post will be the first of a series entitled “Captivated by Colour” where we explore each of the fancy diamond colours in turn, together with what gives the diamonds their colours, where they come from, what the prices of coloured diamonds are and, of course, some famous coloured diamonds.
Whilst most coloured diamonds are exceptionally expensive (especially in South Africa with our weak currency), yellow diamonds are perhaps the most affordable of the fancy colours (except for black diamonds, of course), so we’ll kick off our series with yellow.
What gives yellow diamonds their colour?
Diamonds are the purest gemstone we know of, made almost exclusively of carbon. When a diamond grows in the mantle of the earth, in what can only be described as a “chemical soup mix”, it’s only natural that other elements may be incorporated into the diamond as it grows. When the element nitrogen is incorporated during diamond growth, the diamond will turn yellow. The higher the proportion of nitrogen in the diamond, the more yellow it will be. It’s important to note that yellow diamonds are not any “weaker” or less hard because they have a small percentage of nitrogen in their composition; we’re looking at tiny parts per million (ppm) proportions of nitrogen.
Where do yellow diamonds come from?
South Africa’s diamond rush was triggered in 1867 when Erasmus Jacob’s discovered our very first diamond. The “shiny pebble” he found in a river bed turned out to be a 21.25ct yellowish-brown diamond, which was cut into a 10.73ct gemstone. Since then, South Africa has been a prolific producer of some of the most vivid yellow diamonds available today. Other countries that produce yellow diamonds include Australia, Angola, the DRC and Canada.