| Devilline | |
| Category: | Sulfate minerals |
| Formula: | CaCu4(SO4)2(OH)6·3(H2O) |
| Imasymbol: | Dev[1] |
| Strunz: | 7.DD.30 |
| System: | Monoclinic |
| Class: | Prismatic (2/m) (same H-M symbol) |
| Symmetry: | P21/c |
| Unit Cell: | a = 20.870, b = 6.135 c = 22.91 [Å], β = 102.73° V = 2,861.23 Å3 |
| Color: | Green, blueish green; green in transmitted light |
| Habit: | Prismatic, lamellar, platy pseudohexagonal crystals |
| Twinning: | On |
| Cleavage: | Perfect (001) distinct (110) and (101) |
| Tenacity: | Brittle |
| Mohs: | 2.5 |
| Luster: | Vitreous, pearly |
| Refractive: | nα=1.585, nβ=1.649, nγ=1.660 |
| Opticalprop: | biaxial negative |
| 2V: | 42° |
| Birefringence: | δ=0.075 |
| Pleochroism: | Visible |
| Streak: | Light green |
| Density: | Measured: 3.13 g/cm3Calculated: 3.084 g/cm3 |
| Solubility: | Insoluble in water and concentrated H2SO4. Completely soluble in HNO3. |
| References: | [2] [3] |
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.[4] 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.[5] 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 minerals are monoclinic sulfates.[6]
| Mineral | Chemical formulae | Crystal system | |
|---|---|---|---|
| Cu4Mn2+(SO4)2(OH)6·4H2O | Monoclinic | ||
| Devilline | CaCu4(SO4)2(OH)6·3H2O | Monoclinic | |
| Cu5(SO4)2(OH)6·4H2O | Triclinic | ||
| Zn(Cu,Zn)4(SO4)2(OH)6·6H2O | Monoclinic | ||
| PbCu4(SO4)2(OH)6·3H2O | Monoclinic | ||
| Ca(Cu,Zn)4(SO4)2(OH)6·3H2O | Monoclinic |