Onyx

The name “onyx” is also frequently used for level-banded (parallel-banded) agates, but in proper usage it refers to color pattern not band structure.

[8] Onyx can be found in various regions of the world, including Greece, Yemen, Uruguay, Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, Pakistan, India, Indonesia, Madagascar, Latin America, the UK, and various states in the US.

The German sculptor Ferdinand Preiss used Brazilian green onyx for the base on the majority of his chryselephantine sculptures.

[18] Green onyx was also used for trays and pin dishes – produced mainly in Austria – often with small bronze animals or figures attached.

[20] Sardonyx (onyx in which white layers alternate with sard - a brownish color) is mentioned in the Bible as well.

[22] The first-century naturalist Pliny the Elder described both types of onyx and various artificial treatment techniques in his Naturalis Historia.

[11] Slabs of onyx (from the Atlas Mountains) were famously used by Mies van der Rohe in Villa Tugendhat at Brno (completed 1930) to create a shimmering semi-translucent interior wall.

The ancient Romans entered battle carrying amulets of sardonyx engraved with Mars, the god of war.

Cabochons of red onyx, also called sardonyx
A photograph of 6 smooth black pebbles with white markings, arranged in a circle
Black onyx with white streaks
A photograph showing a roughly rectangular gem set in a gold frame with 2 carved panels with various figures carved in shallow from translucent white chalcedony against a solid black background
The Gemma Augustea is a Roman cameo produced 9–12 AD and carved in a two-layered onyx gem (19 × 23 cm)