VARISCITE on CRANDALLITE, ITUMBIARA GOIAS BRAZIL (small cabinet)

Variscite is a hydrated aluminum phosphate mineral, specifically represented as AlPO4·2H2O. This mineral is relatively uncommon and is sometimes mistaken for turquoise; however, variscite typically exhibits a greener hue, attributed to trace amounts of trivalent chromium (Cr3+).

Geologically, variscite is a secondary mineral that forms through the direct deposition of phosphate-rich water interacting with aluminum-rich rocks in near-surface conditions. It is found as fine-grained aggregates within nodules, as cavity fillings, and as crusts. Additionally, variscite often features white veins of crandallite, a calcium aluminum phosphate mineral.

Crandallite is a mineral composed of calcium, aluminum, and basic phosphate, with the chemical formula CaAl3(PO4)2(OH)5·H2O. It is named in honor of Milan L. Crandall Jr., a contributor at Knight Syndicate. This mineral typically occurs in laterite formations and as a result of the alteration of phosphate-rich pegmatites.