What is Onyx?
Onyx is a form of chalcedony, a semi-precious stone that showcases alternating bands of color in a straight manner. Some of the most common shades include white, black and brown. Chalcedony is basically the family name of stones wherein their formation is from quartz or silicon dioxide. For a particular stone to be classified as chalcedony, it must be translucent to transparent with milky feature or appearance. Oftentimes, the characteristic of the stone is highlighted with layers of color.
Onyx is characterized with a shade that is basically formed through whatever impurities that permeate the rock during its formation process. It is known that the most classic combination of shades that characterize this stone includes red and brown layers, which alternate with white. The formation is likewise known as sardonyx. Why sardonyx? The red band color is actually representing sard, which is another form of chalcedony. There are however much rarer types of this specific stone, which have the mixture of, black bands. It could be combined with other colors or you just plain and primary black. The black onyx variation is actually much highly prized because it is used for ornaments and jewelries.
The stone is also simulated through chemical and heat treatment to create its color. Therefore, you would find it very hard to tell whether you are dealing with a dyed treated or heat treated stone. Moreover, dealers of this piece could never disclose the process used to form it. Although it is much beautiful and stunning to simulate the color, most people prefer that they have naturally colored rocks.
Onyx is also reasonably hard however, it must also be cared for through avoiding excessive exposure to chemicals and sunlight. It is also quite demanding in terms of maintenance since periodic cleaning and polishing is a must.