Onyx the word it's self means nail. Greek language it's benefical to skin, nail and hair it belongs to oxite mineral family and consist of mangan calium, it's volcanic and mineral family stone having 6.5° hardness and and 2.5° instenty, it's taken out from Brazil, India, Arabia and Turkey in tehe world. In Turkey it's taken from out Bolu, Manisa, Balikesir and specialy cappadokcia. It has twelwe different colours in the world an seven of them are from cappadocia.
Exept Blue it has several colour. It's formed of the minerals that rivers bring. Onyx is different from marbie and alabastion. An importent thing abaut this stone is being transluosoud at firgt it's surface is rough but after polihig it resembles glass and the stone take it's natural colour, it exist 5- 40 m deepness of under-ground beaucouse of the minerals that is consist of only black onyx isn't transluosoud .As it is one of the hardest stone in the world it can only be cut with diamand blade. Adding to these we can say that. It's a fibrous stone.