Black Diamond: Fire, Colour & Scintillation.
Solitaire Magazine Asia-Pacific
December January 2006 Archive
Story P.J Joeseph
BLACK diamond is a variety of diamond that was once held in low esteem. Today, however, it has found favour amongst some of the world’s innovative jewellers. The credit goes to Swiss jeweller Fawaz Gruosi, who started the trend with his one-of-a-kind black diamond jewellery collection and watches. Since then, black diamond has been catapulted into the world of fine jewellery, and is no longer just a by-product of mining.
Colour The colour of black diamond ranges from grey to black. Darker, even shades are more desirable.The presence of numerous inclusions, sometimes lining cleavages and fractures, results in the black colour. Natural black diamonds are heavily included, while pure black, a rarer type, may look similar to black onyx. To judge colour, use a transmitted, reflected and fibre-optic light source to observe the colour contrast. The best natural black diamonds are not easy to find.Cut Black diamonds are cut brilliant and in other popular shapes, depending on the size and shape of the rough. They are very hard to polish and require great care in setting. They are widely used in pave settings. In order to simulate an antique look, black diamonds are also cut briolette for necklaces and earrings.
Clarity Pits, cavities and polishing lines, visible under magnification, are due to cleavages, fractures and other inclusions (graphite). The variable presence of magnetite, hematite and native iron may cause unusual magnetic properties.
Such properties may be useful for differentiating natural black diamond from artificially coloured ones.
Treatments
Black diamonds can be treated by irradiation to enhance their colour. Artificially irradiated stones may show a very dark green colour under fibre-optic or a transmitted light source.
Unfortunately treated black diamonds are also used in antique jewellery reproductions, and as replacement stones in old settings. All treatments should be disclosed.
Synthetic and Simulants
Synthetic black diamond is opaque. Proper magnification and fibre-optic lighting may reveal metallic flux inclusions.The most frequently encountered simulants are synthetic black (non-transparent) cubic zirconia, black onyx, hematite and imitation hematite. Most simulants can be distinguished based on gemological properties.
| BRAHMA’S WRATH The Black Orlov, also known as the Eye of Brahma, is possibly the world’s most notorious black diamond. Believed to be cursed, the stone had seen three of its former owners die violent deaths.Legend has it that the jewel’s cursed history began when a monk removed the original 195ct rough from the eye of Hindu idol Brahma, from a shrine in India about 2 centuries ago.By Agustina Soemarko |
Buying Tips
– Use transmitted, reflected and fibre-optic light source to view the colour contrast between treated, natural black diamond and simulants.– Use 10x magnification to view the stone’s overall appearance. Uneven colour and a spotty surface may indicate it is not a natural black diamond. Black diamonds have numerous black inclusions; non-included areas varies from light grey to colourless.– Diamond simulants, both loose and mounted, are sometimes mixed together with natural diamonds, so be cautious with secondhand or estate jewellery.
– As always, if you are doubtful, have the diamond checked by a reputed gem-testing laboratory. S
This article has been vetted for accuracy by Marc Brauner, CEO of the International Gemological Institute.
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Categories: Natural Color Diamonds, ~ Black Diamonds
Tags: black diamond, diamond jewellery, ~ Black Diamonds
