Rosasite is a copper-zinc carbonate closely related to aurichalcite but typically forming more solid botryoidal crusts and small spherical aggregates rather than acicular sprays. Color ranges from sky-blue to vivid blue-green.
Properties
- Formula: (Cu,Zn)2(CO3)(OH)2
- Crystal system: Monoclinic
- Hardness: 4.5
- Color: Sky-blue, blue-green, turquoise-green
- Streak: Pale blue
- Luster: Silky to vitreous
- Cleavage: Good on {110}
- Density: 4.0 – 4.2 g/cm³
Occurrence
Type locality: Rosas mine (Sardinia). World-class material from Mina Ojuela (Mapimí, Mexico) — botryoidal blue-green crusts on goethite, often with aurichalcite. Also Tsumeb (Namibia) and the 79 Mine (Arizona).
Identification
Botryoidal blue-green crusts + softness + association with smithsonite and aurichalcite in the Pb-Zn oxidation zone. Harder than aurichalcite (4.5 vs. 1-2). Distinguish from chrysocolla (lower density, amorphous).
Collector Notes
Mapimí rosasite spheres on goethite are the modern collector standard. Often paired in displays with aurichalcite, hemimorphite and smithsonite to illustrate the Pb-Zn oxidation suite.
Found at these Localities
- Lavrion (Laurium) (拉夫里翁古铅锌银矿)
- Bisbee (Warren District) (比斯比铜矿)
- Mina Ojuela, Mapimí (马皮米奥胡埃拉矿)
- Tsumeb Mine (楚梅布矿)
