Black onyx is the most popular form of onyx today, with a dark silky lustre that contrasts beautifully with the creamy whiteness of classic pearls.
Onyx is a variety of the chalcedony gemstone, which is a species of microcrystalline quartz that also includes different coloured Agates and Jasper. Found in bands that run parallel to each other, and mined mostly in the USA, Brazil, Madagascar, Uruguay and India, the colour of the chalcedony bands can range widely from reds, greens and blues to shades of white and grey. The red brown variety of onyx is known as sardonyx.
The onyx stone is slightly translucid, which perhaps inspired the Ancient Greeks to give it its name. Legend tells that Cupid cut the fingernails of Venus whilst she was sleeping and the discarded clippings were turned into stone by the gods. It is a relatively hard and durable stone, has a silky lustre and has been used and carved for centuries for setting in jewellery.
Black onyx itself is a deep rich black but, from ancient times and still today, this is mostly achieved through enhancement with heat and other colour treatments to achieve its stunning uniform dark colour.
Onyx jewellery can be very affordable and desirable, with an ability to match most colours or to highlight a sparkling white diamond and other brightly coloured gemstones such as a pink ruby. Black onyx can also work well with both yellow and white gold and is a favoured choice for elegant evening wear.
We love the contrast of how a lustrous white pearl can be flattered by the deep darkness of black onyx. The ‘black and white’ style created by the effect of combining onyx, pearls and diamonds has been widely used for jewellery design since the Art Deco 1920s and 1930s. Cartier, in particular, has worked with onyx since the 1910s and continues to choose this gem for its outstanding designs.