Onyx is most commonly colored black or black with white bands, but it is also available in red and brown. These variations are sometimes called sardonyx.
Onyx is available in different sizes and shapes. It is a hard stone, which is moderately resistant to damage and measures 7.0 on Moh's hardness scale. Onyx is formed from quartz, and is the most common type of mineral in the world, accounting for 12 percent of the Earth's crust. While most regions of the world have deposits of onyx, the main regions of production are the United States, Brazil, India, Pakistan, Sri Lanka and Madagascar.