|
Chemical formula
|
SiO2 _ |
|
Crystalline system
|
trigonal |
|
Class
|
oxides |
| Origin | Minas Gerais, Brazil |
| Size |
Medium : 3.0-4.0 cm big : 4.0-5.0cm |
Massive dark colored Onyx.
In principle, the onyx is considered as a variety of agate or chalcedony.
The piece you receive may differ slightly from the photo shown as the minerals are natural and no piece is identical. The size is approximate.