Pentagonite crystals on Stilbite, India
A very nice specimen of electric blue radial prismatic Pentagonite crystals on white Stilbite from Poona, India.
Pentagonite is a dimorph of Cavansite. It has a formula of Ca(VO)Si4O10•4H2O. (A dimorph is a mineral with the same composition as another mineral but a different chemical structure.) Pentagonite was named for the pseudosymmetrical five-fold habit of typical pentagonite twins.
Measures 2 7/8 x 2 x 1 inches.
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