Devilline

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
Devilline
General
CategorySulfate minerals
Formula
(repeating unit)		CaCu4(SO4)2(OH)6·3(H2O)
Strunz classification7.DD.30
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/c
Unit cella = 20.870, b = 6.135
c = 22.91 [Å], β = 102.73°
V = 2,861.23 Å3
Identification
Colorgreen, blueish green; green in transmitted light
Crystal habitprismatic, lamellar, platy pseudohexagonal crystals
TwinningOn {010}
Cleavageperfect (001) distinct (110) and (101)
TenacityBrittle
Mohs scale hardness2.5
Lustervitreous, pearly
Streaklight green
Densitymeasured- 3.13 g/cm3 calculated- 3.084 g/cm3
Optical propertiesbiaxial negative
Refractive indexnα=1.585, nβ=1.649, nγ=1.660
Birefringenceδ=0.075
Pleochroismvisible
2V angle42°
SolubilityInsoluble in water and concentrated H2SO4. Completely soluble in HNO3.
References[1][2]

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.

Devilline group

Devilline group minerals are monoclinic sulfates.[5]

MineralChemical formulaeCrystal system
CampigliaiteCu4Mn2+(SO4)2(OH)6·4H2OMonoclinic
DevillineCaCu4(SO4)2(OH)6·3H2OMonoclinic
KobyasheviteCu5(SO4)2(OH)6·4H2OTriclinic
KtenasiteZn(Cu,Zn)4(SO4)2(OH)6·6H2OMonoclinic
LautenthalitePbCu4(SO4)2(OH)6·3H2OMonoclinic
SerpieriteCa(Cu,Zn)4(SO4)2(OH)6·3H2OMonoclinic

References
  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
  5. Back, Malcolm E. (2014). Fleischer’s Glossary of Mineral Species (11 ed.). Tucson AZ: Mineralogical Record Inc. p. 434.


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