Gemmologist’s Corner – Black Onyx

Black Onyx is one of my favourite materials used in jewellery, especially when mixed with diamonds, it offsets the sparkle of the diamonds beautifully and was often used in rings in my favourite jewellery period – Art Deco.

Onyx is a variety of agate, which is a banded form of microcrystalline quartz, the coloured layering of this material lends itself to three-dimensional carving such as cameos and makes it a popular ornamental material. ‘Onyx’ is the term often used when referring to only black, non-banded microcrystalline quartz. This is in the strictest sense incorrect, but it is so widely used and understood that it is commonly accepted.

This black ‘onyx’ has been very popular in jewellery for centuries – the Victorians employed it in the second half of the 19^th Century as the colour black reflected Queen Victoria’s sadness at the loss of her beloved Prince Albert.

Its popularity continued into the 20^th Century; however, its use became less melancholy and was used by Cartier and other big jewellery house of the time in the bold striking designs popular of the new century and innovation that came with it. It was often used alongside materials such as rock crystal, lapis, coral, jade and other less expensive materials or to offset other more expensive precious materials such as diamonds and coloured gemstones. It’s use continues after the 1^st and 2^nd world wars as these types of materials were useful to jewellers as more expensive materials were harder to find.

Today it is only occasionally possible to find these one-off vintage pieces containing onyx so if you spot one do not let it pass you by! They are still as stylish and timeless as the day they were crafted.

Lot 200 is one of the nicest examples of an onyx and diamond ring from the early 20^th century, it contains a 1.64 carat old cut diamond with a surround of black onyx , the estimates guides €4000 – 6000.

If that is out of your budget lot 192 is vintage onyx ring with a small diamond to the centre guiding €150 – 200.

In a modern twist we also have a pair of 18ct gold and onyx Italian design cufflinks modelled as vintage motor cars, their guide is €1200 - 1400