Synthetic stones are created artificially in a factory or laboratory, but have the same physical, chemical and optical characteristics as their natural counterparts. These stones usually have high luster, and is difficult to tell the difference from natural stones with the naked eye.
Onyx is a banded variety of the oxide mineral chalcedony. The colors of its bands range from white to almost every color (with the exception of some shades, such as purple or blue). Commonly, specimens of onyx contain bands of black and/or white.