Psilomelan
Under Psilomelan is meant a hard manganese ore that different from a mixture of manganese oxide is. However, since it mainly contains the mineral romanèchite , which is also known by the synonym Black Glass Head , psilomelan is sometimes also called that. As it is a mixture of different minerals, psilomelan is no longer viewed as a separate mineral.
Psilomelan usually occurs in compact, opaque masses of earthy or fine-grained consistency, but can also be found in the form of stalactitic or dendritic aggregates from black to brownish-black in color. Fresh samples sometimes have a metallic sheen . The chemical composition for psilomelan is given as (Ba, H 2 O) 2 Mn 5 O 10 .
Special properties
When psilomelan powder is heated in a test tube , water vapor is released which condenses on the walls of the glass. It is soluble in hydrochloric acid (HCl) with evolution of chlorine .
Education and Locations
Like pyrolusite, psilomelan is a typically sedimentary mineral. However, it can also be formed secondarily in the oxidation zone of other manganese minerals.
Large deposits of psilomelan are mainly in Georgia and Ukraine . In Germany, there are major deposits in the Black Forest ( Eisenbach ) and the Saxon Ore Mountains .
use
Where psilomelan occurs in larger quantities, the mineral is broken down to produce manganese.
Individual evidence
- ↑ Mineral Atlas: Black Glass Head
- ↑ Rudolf Graubner: Lexicon of Geology, Minerals and Rocks . Emil Vollmer Verlag GmbH, Munich 1980, ISBN 3-87876-327-1 , p. 304 .
Web links
- Mineral Atlas: Psilomelan (Wiki)