Minerals identify

Know how to recognize them

Birnessite

Oxide mineral

Birnessite (Na0.3Ca0.1K0.1)(Mn4+,Mn3+)2O4 · 1.5 H2O is an oxide mineral, potassium. It has a dark brown to black color with a submetallic luster. It is also very soft, with a Mohs hardness of 1.5. Birnessite is formed by precipitation and groundwater and is a major component of desert varnish.

Identification

Color of mineral

Brown
Black

Mohs scale ( mineral hardness )

1.5

Density ( specific gravity )

1.73
1.69

Luster ( interacts light )

Metallic
Dull

Crystal ( diaphaneity )

Monoclinic