Devilline

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Devilline
Devilline-t08-23b.jpg
Devilline
General
Category Sulfate minerals
Formula
(repeating unit)
CaCu4(SO4)2(OH)6·3(H2O)
Strunz classification 07.DD.30
Crystal symmetry monoclinic, 2/m
Unit cell a=20.870 Å, b=6.135 Å, c=22.91 Å, β=102.73°, V=2,861.23 ų
Identification
Color green, blueish green; green in transmitted light
Crystal habit prismatic, lamellar, platy pseudohexagonal crystals
Crystal system Monoclinic
Twinning On {010}
Cleavage perfect (001) distinct (110) and (101)
Tenacity Brittle
Mohs scale hardness 2.5
Luster vitreous, pearly
Streak light green
Density

measured- 3.13 g/cm3

calculated- 3.084 g/cm3
Optical properties biaxial negative
Refractive index nα=1.585, nβ=1.649, nγ=1.660
Birefringence δ=0.075
Pleochroism visible
2V angle 42°
Solubility Insoluble in water and concentrated H2SO4. Completely soluble in HNO3.
References [1] [2]

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.[3] 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.[4] Because Devilline occurs in such oxidation zones, this mineral often is of post-mining origin. Devilline is found in mines all around the world.

References[edit]

  1. ^ http://www.mindat.org/min-1270.html
  2. ^ http://webmineral.com/data/Devilline.shtml
  3. ^ Back, M., and Mandrine, J. (2008) Fleischer's Glossary of Mineral Species 2008. 58 p. Mineralogical Record, Tuscan, Arizona
  4. ^ http://www.handbookofmineralogy.org/pdfs/devilline.pdf