Mineral Species: Rosasite

Chemical Formula: (Cu,Zn)2CO3(OH)2

Chemical Name: Copper Zinc Carbonate Hydroxide

Mineral Class: Carbonate

Mineral Notes: Rosasite forms in the oxidation zones of copper-zinc deposits. It typically occurs as crusts and botryoidal masses or nodules. Crystals are fibrous and found in tufted aggregates. The colour is an attractive bluish green. Rosasite is associated with Limonite and other colourful zinc minerals including Aurichalcite, Smithsonite and Hemimorphite. Rosasite can be confused with Aurichalcite but it is usually more massive not lamellar. Rosasite crystals are also much harder than Aurichalcite. 

Description: A very rich specimen of blue-green Rosasite on a brown matrix. The mineral forms large nodular aggregates lining the sides of several vugs in the matrix surface. Many of the nodules have a peal-like luster and a degree of chatoyancy.

Location: Mapimi, Durango, Mexico.