Information about Onyx

Onyx is a variety of chalcedony, a microcrystalline form of quartz, recognized for its striking, parallel banding that typically alternates between black and white.

It is known for its smooth texture, fine grain, and a waxy to vitreous luster.

While black and white banding is the most common, onyx can also display other color variations, including brown, red, and beige, some of which are given other trade names.

A warning!

It is well worth pointing out that other forms of banded (or sometimes, non banded!) materials have recently been sold as onyx.

The vast majority of beige-brown banded material sold as onyx is in fact banded calcite from Mexico and Pakistan – this is a decorative stone and often sold carved, but it is significantly softer than actual onyx, as well as being entirely chemically different.

Names for this material sometimes include terms like ‘mexican onyx’ or ‘onyx marble’.You can read an article about the difference between onyx and calcite here.

Uses and History

Onyx has been used for centuries in jewellery, carvings, and decorative objects. It is commonly fashioned into rings, pendants, and cameos due to its striking banded patterns.

Historically, onyx was also used for seals and amulets, believed to offer protection and strength.

The name “onyx” is derived from the Greek word “onux,” meaning “fingernail,” due to its translucent, flesh-coloured varieties – pinks and reds for ‘sardonyx’.

Onyx has been used since antiquity, valued in ancient Egypt, Greece, and Rome for crafting decorative objects, inlays, and ceremonial items.

During the Victorian era, black onyx was particularly popular for mourning jewellery, alongside whitby Jet. Its timeless appeal continues to make it a treasured material in modern design.

Mineralogy

Hazards and Warnings

A financial warning – often produced by soaking agates in dye – use acetone to check this.

Mineral collectors should wash their hands after handling specimens, to avoid any exposure to potential toxins.

Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis.

When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.

Translations

Further Reading / External Links

• https://www.mindat.org/min-2999.html
• https://en.wikipedia.org/wiki/Onyx
• https://www.minerals.net/gemstone/onyx_gemstone.aspx