Plancheite Locality: Kambove , Central area, Katanga Copper Crescent, Katanga (Shaba) , Democratic Republic of Congo (Zaïre) ( Locality at mindat.org ) Size: 10.9 x 7.2 x 6.9 cm. An exceptionally large and rich specimen of solid plancheite forming veins and large globular clusters. Old material from this well-known locality. Ex. Marvin Rausch Collection. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Plancheite
A blue hydrated copper silicate closely related to — and often confused with — shattuckite.
Intro adapted from Wikipedia (CC BY-SA).
Plancheite is an IMA-recognized mineral species in the silicate class, with the chemical formula Cu₈(Si₄O₁₁)₂(OH)₄·H₂O.
It crystallizes in the orthorhombic crystal system (space group Pcnb). It is a member of the Plancheite structural group.
Key properties: Mohs hardness 6; specific gravity 3.65–3.8; Satiny luster; refractive index 1.696; optically biaxial.
IMA symbol Pch, IMA status: approved, named in 1908.
A rare secondary mineral found in the oxidized portion of copper deposits.
It is found associated with Chrysocolla, dioptase, malachite, conichalcite, tenorite.
The name refers to a Mr. Planche, who provided the original material for characterization.