Psilomelane

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The mineral psilomelane is now often called romanchite, named for its discovery location in France. This mineral is a manganese oxide, and is actually a manganese ore. Romanchite forms iron-black, dark steel-gray masses.

Psilomelane Classification
Common Name Psilomelane
Species Psilomelane
Psilomelane Optical Properties
Transparency Opaque
Dispersion Strength: None
Refractive Index Over The Limit 2.110-2.260
Pleochroism None
Psilomelane Characteristic Physical Properties
Hardness 6-7
Streak Brownish Black To Black, Shiny
Specific Gravity 6.400-6.450
Toughness Poor
Inclusions Psilomelane is sometimes botryoidal and might have pyrolusite bands or swirls.
Luster Dull, Metallic
Fracture Uneven
Cleavage None
Psilomelane Chemistry & Crystallography
Chemical Name manganese oxide
Chemical Formula (Ba, H2O2)Mn5O10
Crystal System Monoclinic
Chemistry Classification Oxide

Countries of Origin

United States of America (the); Unknown; China; Mexico

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Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.