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Facts About Loose Black Coloured Diamonds

Black diamonds typically are completely opaque, with a high lustre that gives the stones an almost metallic appearance. They have become more popular over recent years due to their low price point and strong, bold colour. Unlike other Fancy colours such as Blue and Pink Argyle diamonds, the beauty of Black is in their crystal pure colour and surface lustre. Black stones are divided into two main groups: Natural Black and Treated Black diamonds.

Natural black diamonds are actually quite different than other coloured diamonds.

Research into the cause of colour in black diamonds is relatively recent. Today we know that most naturally coloured black diamonds get their colour from large quantities or clouds of minute mineral inclusions such as graphite, pyrite or hematite that extend throughout the stone. These diamonds may also have numerous cleavages or fractures that are stained black or have become black because of graphitization. It is the concentrations of these internal features that are responsible for the colouration. In fact, the actual body colour of a natural black diamond may range from near-colourless to brown or “olive” green.

Treated black diamonds are regular white diamonds that are usually of extremely low value due to the high amount of inclusions in them. Since they have so many inclusions, as white diamonds the only use for them is as industry grade, however, with the help of high pressure, high temperature (HPHT) treatment they turn a pure black colour.

These treated black diamonds are typically what you see in the retail jewellery marketplace. Because these diamonds are so heavily included, cutting and polishing can prove difficult. When searching for these sorts of diamonds pay particular attention to the polish and avoid where possible surface blemishes, particularly in the crown of the stone.

Are Black Diamonds Rare?

+ How Rare Are They?

Natural black diamonds that haven’t undergone treatment are actually quite rare and can be difficult to source. Because they haven’t been heated they don’t have what you would call that crystal black colour and appear more ‘muddied’ or ‘speckled’ in opaque dark greys, browns, and greens. For this reason, they aren’t typically searched for and in turn, there isn’t a large inventory in the local market. Treated black diamonds are more readily supplied as they are what most consumers are searching for.

+ Are They Expensive?

Out of all the coloured diamonds, black is certainly the most cost effective, particularly in treated goods. Due to the nature of the treated material being so heavily included and quite abundant, the price per carat is very affordable and can allow for a significant stone within a smaller budget. Natural black diamonds attract a much higher price point, but still more cost effective than white diamonds.

+ Are There Alternate Gemstones You Can Recommend?

A couple of options to consider here; the first being natural Black Spinel and the advantage with this option, is the material is much cleaner and therefore easier to polish with far less surface blemishes. The second option would be Australian Sapphire in deeper blue and/or green colours and other dark hues.

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