Connellite is a rare mineral species, a hydrous copper chloro-sulfate,[6] Cu19(OH)32(SO4)Cl4·3H2O, crystallizing in the hexagonal system. It occurs as tufts of very delicate acicular crystals of a fine blue color, and is associated with other copper minerals of secondary origin, such as cuprite and malachite. Its occurrence in Cornwall, England, was noted by Philip Rashleigh in 1802, and it was first examined chemically by Prof Arthur Connell FRSE in 1847, after whom it is named.[6]
| Connellite | |
|---|---|
 | |
| General | |
| Category | Halide mineral |
| Formula (repeating unit) | Cu19(OH)32(SO4)Cl4·3H2O |
| IMA symbol | Cnl[1] |
| Strunz classification | 3.DA.25 |
| Crystal system | Hexagonal |
| Crystal class | Dihexagonal dipyramidal (6/mmm) H-M symbol: (6/m 2/m 2/m) |
| Space group | P63/mmc |
| Unit cell | a = 15.78 Å, c = 9.10 Å; Z = 1 |
| Identification | |
| Color | Azure blue, blue green |
| Crystal habit | Clusters of divergent acicular crystals, fibrous, crusts |
| Cleavage | None |
| Fracture | Splintery |
| Tenacity | Brittle |
| Mohs scale hardness | 3 |
| Luster | Vitreous |
| Streak | Pale green-blue |
| Diaphaneity | Translucent |
| Specific gravity | 3.36 to 3.41 |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 1.724 – 1.746 nε = 1.738 – 1.758 |
| Birefringence | δ = 0.014 |
| References | [2][3][4][5] |
The type locality is Wheal Providence at Carbis Bay in Cornwall.[4] Outside Cornwall it has been found in over 200 locations worldwide including Namaqualand in South Africa and at Bisbee, Arizona (US).[4]
References
edit- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Connellite Mineralienatlas
- ^ Connellite in the Handbook of Mineralogy
- ^ a b c Connellite: Connellite mineral information on Mindat.org
- ^ Connellite data on Webmineral
- ^ a b One or more of the preceding sentences incorporates text from a publication now in the public domain: Chisholm, Hugh, ed. (1911). "Connellite". Encyclopædia Britannica. Vol. 6 (11th ed.). Cambridge University Press. p. 963.