Mineral
Cavansita
Ca(VO)Si₄O₁₀·4H₂O · Fosfosilicatos
Cavansite is the close 'twin' of pentagonite. The two are dimorphs: they share the same chemical composition but crystallise differently under differing formation conditions, chiefly temperature. Cavansite forms deep blue radial-acicular rosettes.
Etymology
Acronym formed from calcium, vanadium and silicate, in direct reference to its composition.