What is Shattuckite?
Shattuckite is a vivid blue copper silicate, valued for botryoidal crusts, fibrous texture and polished ornamental material from oxidised copper deposits.
Mineralogy and crystal structure
Reference formula: Cu5Si4O10(OH)2. Shattuckite is orthorhombic and commonly occurs with chrysocolla, malachite, azurite and quartz. The existing COD-backed structure is retained; colour and compactness vary with intergrowths. Shattuckite is classified with silicates and has a orthorhombic crystal system. Typical hardness is 3.5–4 on the Mohs scale and specific gravity is approximately 3.8–4.1.
Colour, lustre and habit
Typical colours include blue, blue-green, turquoise, green. The usual fibrous, botryoidal, massive habit and vitreous, silky, dull lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Shattuckite forms in or is associated with supergene oxidation zones above copper sulfide deposits. Important documented localities include Arizona in the United States, Namibia, the Democratic Republic of the Congo, Mexico and South Africa.
Electric blue from a copper oxidation zone
Shattuckite is commercially effective because its colour is immediate and its botryoidal texture polishes well. Matrix, association and the boundary between pure shattuckite and mixed copper silicates matter.
Collecting and care
Protect from scratches, acids and harsh cleaners. Avoid dust-producing work and clean with a soft damp cloth.
