Tungusite Locality: Newbury Park, Ventura Co., California, USA Green Tungusite. Field of view 5 mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Tungusite
Tungusite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₁₄Fe²⁺₉Si₂₄O₆₀(OH)₂₂.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Gyrolite structural group.
Key properties: Mohs hardness 2; specific gravity 2.59; Slightly pearly on flakes luster; optically uniaxial.
IMA symbol Tgu, IMA status: approved, named in 1966.
A secondary mineral forming crusts lining cavities and amygdules in hydrothermally altered basalts.
It is found associated with Analcime, apophyllite, gyrolite, calcite, quartz.
The name refers to the Tunguska River, Russia.