Cavansite

minerals

phyllosilicate

vanadium

zeolite

Formula: Ca(V4+O)(Si4O10).4H2O
Phyllosilicate (sheet silicate), paramorph of pentagonite
Specific gravity: 2.21 to 2.31
Hardness: 3 to 4
Streak: Bluish white
Colour: Blue to greenish blue
Solubility: Slightly soluble in acids
Environments:

Volcanic igneous environments
Basaltic cavities

Cavansite occurs as a secondary mineral in basalt and in andesite, associated with zeolites, and also in tuff (Dana, Webmin).

Localities

At the Wagholi quarry, Pune district, Maharashtra, India, in a few places the dense basalt has been interuptuded by small breccia zones. In these the rock has been washed out by hydrothermal solutions, favouring the deposition of stilbite, heulandite and cavansite, and less frequently, mordenite and calcite. The Deccan basalts have an average vanadium content of 300 ppm, but in the Pune area the concentration is much higher at 600 to 750 ppm. Other than cavansite and pentagonite, no minerals with essential vanadium have been found in these basalts. Cavansite is generally found to grow on small heulandite or stilbite crystals, occasionally with calcite. Very rarely cavansite is found embedded in mordenite (Minrec 34.1.41-43). Here cavansite occurs in pores of the altered basalt breccia and tuffaceous andesite associated with stilbite, calcite, heulandite, mordenite and chalcocite (HOM).

At the type locality, the Owyhee Dam, Lake Owyhee State Park, Malheur county, Oregon, USA, cavansite is found in cavities and veinlets in basalt and in tuff partly ̄filling fractures, associated with pentagonite, calcite, heulandite, stilbite, analcime, apophyllite, thomsonite and copper (HOM, Dana, AM 58.405-411).

Back to Minerals