Onyx, Black Gemstone Properties 

Design Possibilities

Black is neutral, making it a great design element to combine with many different colored stones, other gemstone beads, and with both silver and gold. Its deep, dark, lustrous surface can play a striking contrast to the warm-colored gemstones like garnet, carnelian and coral. Or combine it with any of the stones with a black matrix: lapis, rhodonite, Dalmatian jasper, or snowflake obsidian.


The name "onyx" comes from the Greek for "fingernail," referring to the translucence of the white-colored layer of the multi-layered stone. According to myth, Cupid trimmed the nails of the sleeping Venus. The Fates turned those clippings into stone to prevent even a part of Venus from dying.

The Romans were expert at glyptography (the carving of layered stones to reveal different colors) and crafted beautiful seals from onyx (white layer over black base) and sardonyx (white layer over reddish-brown base). The patterns were cut in negative relief. Engravings with a negative picture are called intaglios and those with raised image are cameos. In the Middle East, onyx was associated with sorcerers.

Metaphysical/Healing Properties

Black has been associated with regeneration and new beginnings. Black onyx is thought by some to have protective qualities, making it advantageous to carry when one is traveling. It is said to be useful in fighting basic fears and in helping to create the opportunity to move beyond bad relationships--and to heal old emotional wounds. The Romans associated it with courage and it is thought to be useful when one is defending him/herself against unfair criticism.

Scientific Description

Onyx is a form of chalcedony, which is a microcrystalline quartz. It is formed in the gas cavities of lava. Its multi-layering is similar to that of agates. When the stone has a black base and a white upper layer, it's called onyx. (Black onyx is uniformly black chalcedony.) When the base is brown, it is called Sard-onyx. And carnelian-onyx has a red base.

Much of what is referred to as "black onyx" is gray chalcedony that has been chemically treated to turn it into a rich black. The gray stone can be saturated with a solution of cobalt chlorate and chlorammonium, or it can be immersed for a prolonged period in a sugar solution and then heated in sulphuric acid to carbonize the sugar.
Mineral InformationMicrocrystalline quartz, chalcedony group
Chemical CompositionSiO2
ColorBlack, usually dyed these days
Specific Gravity2.58-2.64
Refractive Index1.530-1.539


Brazil supplies the best multi-colored raw material, but onyx is found worldwide. Gray chalcedony is found in India and China.

Shop for Black Onyx Items

**Please note that all metaphysical or healing properties listed are collected from various sources. This information is offered as a service and not meant to treat medical conditions. Fire Mountain Gems and Beads® does not guarantee the validity of any of these statements.

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