There is a quick guide to buying onyx jewelry and the benefits and uses of it.
The silicate mineral chalcedony is referred to as onyx.There are two types of chalcedony, agate and onyx, both of which have curved bands.The colors of its bands range from black to almost every color.There are bands of black and white in onyx.The term "oyson" has been used to refer to a variety of banded alabaster, marble, obsidian, and opal, as well as materials with contorted banding.[4][5]
The Greek means "claw" or "fingernail" in Latin.It can sometimes look like a fingernail when there are flesh-colored and white bands.The English word "nail" is related to the Greek word.[6]
There are bands of chalcedony in alternating colors.It is composed of fine intergrowths of the minerals.The bands are not as chaotic as those in agates.[7]
There is a variant in which the colored bands are shades of red rather than black.Black onyx is the most famous variety, but it is not as common as onyx with colored bands.Since ancient times, artificial treatments have been used to produce both black and red colors.Most black onyx on the market is not real.[8]
The name has been used to label other banded materials, such as banded calcite found in Mexico, India and other places, and often carved, polished and sold.This material is more readily available than true onyx.The majority of carved items are made of carbonate.[10]
Common chalcedony and plain agates have been used to make artificial onyx types.The techniques were used in Roman times.Treatments for producing black and other colors include soaking or boiling chalcedony in sugar solutions, then treating with sulfuric or hydrochloric acid to carbonise sugars which had been absorbed into the top layers of the stone.These techniques are still used, as well as other dyeing treatments, and most so-called "black onyx" sold is artificially treated.In addition to dye treatments, heating and treatment with nitric acid have been used to lighten or eliminate undesirable colors.[9]
In addition to Greece, Yemen, Argentina, Australia, Brazil, Canada, China, Czech Republic, Germany, Pakistan, India, Indonesia, Madagascar, Latin America, the UK, and various states in the US, there are other regions of the world where oys is found.[2]
It has been used for carving and jewelry for a long time.It has been used for intaglio and hardstone cameo engraved gems, where the bands make the image contrast with the ground.Most of the material in commerce is produced by the staining of agate.[15]
As early as the Second Dynasty, obsidian was used to make pottery items.The use of sardonyx can be seen in the art of Minoan Crete.[17]
Art Deco sculptures were created in the 1920s and 1930s using Brazilian green onyx.Brazilian green onyx was used for the base on most of Ferdinand Preiss' sculptures.The trays and pin dishes were often made with small bronze animals or figures attached.[19]