Cavansite Crystals on Stilbite

Cavansite Crystals on Stilbite
Cavansite Crystals on Stilbite

Cavansite, whose name is derived from its chemical composition, calcium vanadium silicate, is a deep blue hydrous calcium vanadium phyllosilicate mineral, occurring as a secondary mineral in basaltic and andesitic rocks along with a variety of zeolite minerals.

It's blue coloring comes from vanadium, a metal ion. Discovered in 1967 in Malheur County, Oregon, cavansite is a relatively rare mineral. It is polymorphic with the even rarer mineral, pentagonite. It is most frequently found in Pune, India and in the Deccan Traps, a large igneous province.

Formula: Ca(VO)Si4O10·4(H2O)
System: Orthorhombic
Color: Brilliant sky-blue to greenish blue
Crystal habit: Radiating acicular prismatic crystals commonly as spherulitic rosettes
Mohs scale hardness: 3 - 4

From India (Wagholi Quarry, Pune, Maharashtra, India),

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