Minerals identify

Know how to recognize them

Sard

Chalcedony variety

Carnelian (also spelled cornelian) is a brownish-red mineral commonly used as a semi-precious gemstone. Similar to carnelian is sard, which is generally harder and darker (the difference is not rigidly defined, and the two names are often used interchangeably). Both carnelian and sard are varieties of the silica mineral chalcedony colored by impurities of iron oxide. The color can vary greatly, ranging from pale orange to an intense almost-black coloration. It is most commonly found in Indonesia, Brazil, India, Russia (Siberia), and Germany.

Identification

Color of mineral

Brown
Red

Mohs scale ( mineral hardness )

6

Luster ( interacts light )

Vitreous
Dull
Greasy
Silky

Crystal ( diaphaneity )

Trigonal