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Olmiite was officially named as a new species in 2006. It is the Manganese dominant analog of poldervaartite. It is named after the Italian mineralogist Filippo Olmi. The only known location where olmiite is found is the N’Chwaning II mine, Kalahari field, Republic of South Africa.

Olmiite Polished
Olmiite Classification
Common Name Olmiite
Species Olmiite
Olmiite Optical Properties
Transparency Translucent-Transparent
Refractive Index 1.663-1.694
Birefringence 0.031
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert to Deep red
Pleochroism None
Olmiite Characteristic Physical Properties
Hardness 5-5.5
Streak White
Toughness Poor
Luster Pearly, Vitreous
Stability Brittle
Fracture Uneven, Irregular
Cleavage None
Olmiite Chemistry & Crystallography
Chemical Name Calcium manganese silicate hydroxide
Chemical Formula CaMn[SiO3(OH)](OH)
Crystal System Orthorhombic
Chemistry Classification Silicate

Olmiite Colors

  • Gray Olmiite Gray
  • White Olmiite White
  • Brown Olmiite Brown
  • Yellow Olmiite Yellow
  • Pink Olmiite Pink
  • Orange Olmiite Orange

Countries of Origin

South Africa


Normal care

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Tim Matthews

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.