Onyx is a variety of chalcedony, a mineral composed of silica. "Onyx" comes from Latin, which in turn comes from ancient Greek "Ónux" meaning fingernail or claw.

They commonly have alternating black and white bands, although these bands can be almost any color.

Onyx has nearly parallel bands, while agate, another variety of chalcedony, has curved bands. Sardonyx is a variety of onyx whose bands are shades of red.

Ancient Greek naturalist Pliny the Elder described onyx as well as specifying methods of imitating this gem using common chalcedony or agate. Today some of these techniques are still used to intensify or change the color of onyx and the red and yellow tones of sardonyx.

Historically, onyx has been used in the making of engraved ornaments and jewelry such as intaglios (when the stone is carved by hollowing like a seal) and cameos (with a raised relief image) since the time of the Romans and ancient Greeks.

It has had a changing reputation depending on culture and time.

In Arabic black onyx is called "El jaza", which means sadness.

In China, slaves and servants mined onyx and it was exported exclusively, as it was believed to produce bad dreams, attract bad luck as well as drain energy.

Due to its somber appearance it gained popularity in the Victorian era for being used in the creation of mourning jewelry for Queen Victoria after the death of her husband Prince Albert.

According to mystics and alchemists, onyx would have the ability to repress and contain all kinds of energy; including spirits and demons.

For Hindus and Persians, it would protect from the evil eye in addition to relieving pain related to childbirth.

Linked to intuition and instinct, it represents support and strength in difficult times and situations of intense physical and mental stress. Its regulating effect optimizes moderation, allowing greater control over passions and emotions.

Shield from harmful influences and energies, it is said to absorb negative thoughts, favoring concentration on the present moment as well as being helpful in meditation.

On the physical level onyx is a booster for the immune system, purifying the kidneys and liver as well as relieving allergies and toning up the nervous system.

Onyx deposits are found in various regions of the world such as in North America, Brazil, United Kingdom, Madagascar and Germany.