Black spinel is not well-known among the gem world, yet its outstanding features make it the ideal choice for an opaque black gem. These days, where most gems undergo routine enhancement treatments, black spinel can stand proud as a gem requiring nothing more than cutting and polishing to bring out its inner beauty. If you want a totally natural and untreated black gemstone – black spinel is the one!
Gemmology matters: Spinel (MgAl2O4) is a mineral similar to corundum (Al2O3) and is often found in ruby and sapphire bearing areas. Spinel comes in a variety of colours but the relatively rare opaque black variety is only found in a few areas – traditionally Thailand is the main source but Australia is also a major producer. With a hardness of 8.0, uniform nature, high reflectance and lack of cleavage, black spinel makes excellent gem material. Black spinel has been often called “black sapphire” or “nin” in Thailand. Miners here often call it Blackjack and regard it as an indicator of good sapphire being present in the wash. Let there be no confusion though as black spinel is an excellent gemstone in its own right.
Mythology and Lore: There is a wealth of mythology surrounding black spinel. It is believed to protect its owner from harm, to reconcile differences, and to console sadness. Some say that black spinel is the stone for people born on Saturday and it is the recommended gift for the 22nd wedding anniversary. While in Western culture, black may be associated with evil or mourning; in other cultures, black may represent power, fertility or wisdom (source Wikipedia). In any case, black is the essence of style and sophistication with a timeless quality that means it will never go out of fashion.
Alternatives in black: There are a number of alternative products to black spinel – all with a number of disadvantages.
(photo at left shows silver earrings with 6 carat cabbed black spinel).
Black Diamonds have become extremely popular in recent years with a price tag to match. Although diamond is the hardest material at 10 on the Mohs scale, the high level of dark coloured inclusions in black diamond weaken the stone making it difficult to cut and polish. Almost all commercially available gems have been heated and irradiated to produce a dark colour and larger gems are difficult to find.
Black Onyx is widely available but inferior for use in jewellery. With a hardness of only 6.5-7.0, onyx is susceptible to damage. Buyers must assume that all commercially available black onyx has been heated and dyed to achieve the black colour as naturally occurring onyx ranges from white to brown, often with striping. Black onyx is the easy option but it is not the best.
Jet was made popular by Queen Victoria who wore it as mourning jewellery after the death of Prince Albert. Jet is really a form of highly compressed coal and is extremely soft (3.0-4.0 Moh) so should be worn with great care to avoid damage.
For those interested in how black gemstones might be used to make a striking fashion statement, here are a few links of interest:
Of course, here at Aussie Sapphire, we have a range of exclusive jewellery featuring black spinel and loose gems which may be used in a jewellery setting of your choice. See our online shop to browse our selection of Black Cat Jewellery and Black Spinel gems.
We hope you found this article of interest – we welcome your comments so feel free to contribute. Stay tuned for the next article which we will probably do on aquamarine.
cheers from Aussie Sapphire