Onyx is a banded variety of chalcedony. The colors of its bands range from white to almost every color (save some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white.
Onyx comes through Latin (of the same spelling), from the Greek ὄνυξ, meaning “claw” or “fingernail”. With its fleshtone color, onyx can be said to resemble a fingernail. The English word “nail” is cognate with the Greek word.
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.
Sardonyx is a variant in which the colored bands are sard (shades of red) rather than black. Black onyx is perhaps the most famous variety, but is not as common as onyx with colored bands. Artificial treatments have been used since ancient times to produce both the black color in “black…
Learn How to Master Skateboarding in a Week-Long Course Are you having problems learning how to skateboard? Is the fear of falling keeping you from progressing? Learn all of the basic principles of skateboarding fast in a one-week camp. We will show you the basics of skateboarding such as how to balance, push, turn, proper […]