Presentation :
Names) :
Marcasite.
Etymology:
From the ancient Arabic name for pyrite and similar minerals used by miners until 1800.
Group, Family:
Marcasite Group.
...
Presentation :
Names) :
Onyx and Sardonyx (variety of chalcedony / variety of agate).
Etymology:
Onyx: From the Greek onux = nail or claw | Sardonyx: Probably from the contracti...
