Black diamond ring
Whilst everyone knows of the common clear (or "white") diamond, many people do not realise that diamonds can also be found in other colours. The most common non-clear diamonds are yellow and brown, which are usually sold for lower prices than clear diamonds as they are not seen as being as beautiful.
Amongst the rarer gemstones are black diamonds, or "Carbonados" to give them their technical name. Black diamonds are not strictly black, but appear black due to small internal structural defects within the lattice of the diamond that give the black diamonds their appearance. Due to their beauty and rarity, black diamond rings can command a high price on the high street.
Although black is usually associated with evil and darkness, black diamond rings are very popular, especially with men looking for something different. When set with clear diamonds, black diamond rings can look extremely striking.
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In contrast to the yellow gold usually used for diamond rings, black diamond rings often use platinum or titanium, as the brighter colour of these metals strikes a much greater contrast with the dark colour of the black diamonds.
The most famous black diamond is the Amsterdam Diamond, which weighs 33.74 carats (around 6.75 grams). It has 145 faces, and has been cut to a pear shape from a rough diamond of 55.58 carats. In 2001 it was sold for $352,000 (US Dollars), which is the highest price ever paid for a black diamond at an auction.
The world's largest cut black diamond is the Spirit of de Grisogono Diamond, which is the fifth largest diamond in the world. It weighed 587 carats (around 117 grams) before being cut, and was 312.24 carats (around 62.45 grams) after cutting. It was set into a black diamond ring with over 700 smaller white diamonds.
Whilst these two black diamonds are well beyond the reach of most of us, you can see more affordable black diamond jewellery here.
Black diamonds are usually only found in Central African Republic and in Brazil, which is surprising as neither of these places are normally associated with diamond mining.