Rosasite is a zinc-copper carbonate hydroxide, occurring in the secondary oxidation zone of copper-zinc deposits. The color is blue-green, and the habit is fibrous. It is named after its type locality, the Rosas mind in Sardinia, Italy.
(Cu,Zn)2(CO3)(OH)2; Hardness 4½; Monoclinic
Gypsum commonly forms in several environments, ranging from sedimentary evaporite deposits to hydrothermal vein deposits. It can occur in massive granular form (alabaster), translucent white crystals (selenite is one variety), and as desert “roses.” It has extensive practical uses, such as fertilizer (for sulfur) and as building material (plaster of Paris, dry wall). Giant crystals of gypsum occur in Mexico’s Cave of Crystals and Cave of Swords.
CaSO4 · 2H2O; Hardness 2; Monoclinic
Malachite is a common copper mineral with a wide occurrence and brilliant green color. It is often banded in appearance and is usually found as crusts or crystal clusters. Can be found as a pseudomorph after azurite crystals.
Cu2(CO3)(OH)2; Hardness: 3.5-4; monoclinic