Onyx

Onyx is a gemstone found in various regions of the world including Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, India, Madagascar, Latin America, the UK, and various states in the US.

Onyx is formed of bands of chalcedony in alternating colors. It is cryptocrystalline, consisting of fine intergrowths of the silica minerals quartz and moganite. Its bands are parallel to one another, as opposed to the more chaotic banding that often occurs in agates.

In jewellery design as in fashion, colours look crisper against a background of black. In fine jewellery, the black backdrop is often supplied by onyx, a black chalcedony quartz with a fine texture.