Outstanding sharp green crystal of the vanadium garnet mineral goldmanite on matrix. From: Rybnícek, Pezinok, Bratislava Region, Slovakia (Slovak Republic). — Photo: David Hospital · CC BY-SA 4.0
Goldmanite
A green vanadium-bearing member of the garnet group.
Intro adapted from Wikipedia (CC BY-SA).
Goldmanite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₃V³⁺₂(SiO₄)₃.
It crystallizes in the cubic crystal system (space group Ia-3d). It is a member of the Garnet structural group.
Key properties: Mohs hardness 7; specific gravity 3.74–3.77; optically isotropic.
IMA symbol Glm, IMA status: approved, named in 1963.
Found in a small metamorphosed U{V deposit in sandstone, embedded in vanadium-rich clays and calcite (Sandy mine, New Mexico, USA); in calcareous metapelites and tungsten-bearing skarns (Coat-an-Noz, France); detrital.
It is found associated with Quartz, calcite, diopside, vesuvianite, wollastonite, epidote, grossular-andradite, biotite, spinel, plagioclase, pyrrhotite, roscoelite.
The name refers to Dr. Marcus Isaac Goldman (1881–1965), American sedimentary petrologist, U.S. Geological Survey.