|Origin||Ojos Negros, Teruel, Spain|
Very highly crystalline specimen of dolomite. Nearly all crystals have a trapezoid shape and pearly luster.
Ojos Negros – large iron mines, worked probably in pre-Roman times, and also in Roman, Medieval and modern times, until 1986. The main mineral in these mines is goethite.
This is a common rock-forming mineral. It is a calcium magnesium carbonate with a chemical composition of CaMg(CO3)2. It is the primary component of the sedimentary rock known as dolostone and the metamorphic rock known as dolomitic marble. Limestone that contains some dolomite is known as dolomitic limestone.