Richtárová, Staré Hory, Banská Bystrica Co., Banská Bystrica Region, Slovakia Photo Copyright © tomas bancik

Chemical Formula: CaCu4(SO4)2(OH)6 · 3H2O
Locality: Cornwall, England, UK
Name Origin: Named after the French chemist, H. E. S. C. Deville (1818-1881). Named from its occurrence at Herrengrund, north of Neusohl, in Slovakia of Czechoslovakia.

Devilline is a sulfate mineral with the chemical formula CaCu4(SO4)2(OH)6 · 3H2O. The name originates from the French chemist’s name, Henri Etienne Sainte-Claire Deville (1818–1881).

Devilline crystallizes in the monoclinic system. Crystallographically, it contains three vectors of unequal lengths and two pairs of vectors are perpendicular while the other pair makes an angle other than 90°. Devilline is prismatic and belongs to the crystal class 2/m. This mineral belongs to the space group P 21/c. Devilline is an anisotropic mineral, meaning that the mineral has different properties in different directions. Optically, this mineral is biaxial negative, meaning that it contains two optic axes. Devilline has a moderate mineral relief. Mineral relief refers to the way a mineral appears to stand out when viewed under polarized light and it is dependent on the mineral’s index of refraction.

Devilline is a rare and unusual secondary mineral found in the oxidized portions of copper sulfide ore deposits. Because Devilline occurs in such oxidation zones, this mineral often is of post-mining origin. Devilline is found in mines all around the world.

Physical Properties of Devilline

Cleavage: {001} Perfect, {110} Distinct
Color: Blue, Blue green, Blue white, White, Dark green.
Density: 3.1 – 3.13, Average = 3.11
Diaphaneity: Transparent
Fracture: Uneven – Flat surfaces (not cleavage) fractured in an uneven pattern.
Hardness: 2.5 – Finger Nail
Luster: Vitreous – Pearly
Streak: light green

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Photos :

LAVENDULAN, SERPIERITE and DEVILLINE Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia, Africa Size: 3.8 x 3.2 x 0.6 cm (Miniature) Owner: Kristalle and Crystal Classics
SERPIERITE and DEVILLINE Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia, Africa Size: 3.8 x 3 x 2 cm (Miniature) Owner: Kristalle and Crystal Classics
DEVILLINE Spania Dolina Ore Belt, Banska Bystrica Region, Slovakia, Europe Size: 6 x 4 x 3 cm (Small Cabinet) Owner: Kristalle and Crystal Classics