Shattuckite (Plancheite): Gemstones Information
Shattuckite is Cu5(SiO3)4(OH)2 and most frequently forms translucent orthorhombic deep to medium aggregates of spherulitic blue masses with two directions of perfect cleavage, hardness 3.5 and SG 3.8–4.12.The RI for the alpha, beta and gamma rays is 1.753, 1.782 and 1.815,biaxial positive. Pleochroism is strong ranging from very pale to deep blue. Shattuckite occurs as a secondary mineral in oxidized copper deposits. Probably the best examples come from the Shattuck mine,Bisbee, Cochise County, Colorado, USA.