CAVANSITE on STILBITE (miniature)

Cavansite, named for its chemical composition of calcium vanadium silicate, is a deep blue hydrous calcium vanadium phyllosilicate mineral that occurs as a secondary mineral in basaltic and andesitic rocks, alongside a variety of zeolite minerals. Its blue color is derived from vanadium, a metal ion. Discovered in 1967 in Malheur County, Oregon, cavansite is considered a relatively rare mineral. It is polymorphic with the even rarer mineral pentagonite and is most commonly found in Pune, India, and in the Deccan Traps, a large igneous province.

Stilbite refers to a group of tectosilicate minerals within the zeolite family. Originally classified as a distinct mineral species until 1997, it was redefined by the International Mineralogical Association to encompass a series, which includes the specific types Stilbite-Ca and Stilbite-Na. Stilbite-Ca, the more prevalent variant, is a hydrous silicate composed of calcium, sodium, and aluminum, represented by the formula NaCa4(Si27Al9)O72·28(H2O). In contrast, Stilbite-Na features a higher sodium content compared to calcium. These two species appear identical to the naked eye, and the term stilbite continues to be used in contexts where detailed testing has not been conducted.

MINIATURE - MINIATURE - MINIATURE