Connellite

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Connellite
Connellite-54486.jpg
General
CategoryHalide mineral
Formula
(repeating unit)
Cu19(OH)32(SO4)Cl4·3H2O
Strunz classification3.DA.25
Crystal systemHexagonal
Crystal classDihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m)
Space groupP63/mmc
Unit cella = 15.78 Å, c = 9.10 Å; Z = 1
Identification
ColorAzure blue, blue green
Crystal habitClusters of divergent acicular crystals, fibrous, crusts
CleavageNone
FractureSplintery
TenacityBrittle
Mohs scale hardness3
LusterVitreous
StreakPale green-blue
DiaphaneityTranslucent
Specific gravity3.36 to 3.41
Optical propertiesUniaxial (+)
Refractive indexnω = 1.724 - 1.746 nε = 1.738 - 1.758
Birefringenceδ = 0.014
References[1][2][3][4]

Connellite is a rare mineral species, a hydrous copper chloro-sulfate,[5] 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.[5]

The type locality is Wheal Providence at Carbis Bay in Cornwall.[3] Outside Cornwall it has been found in over 200 locations worldwide including Namaqualand in South Africa and at Bisbee, Arizona (US).[3]

Connellite crystal structure: Color code: Cu: copper, S: olive, O: red, Cl: green; Cell: magenta

References[edit]

  1. ^ https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Connellite Mineralienatlas
  2. ^ Connellite in the Handbook of Mineralogy
  3. ^ a b c Connellite: Connellite mineral information on Mindat.org
  4. ^ Connellite data on Webmineral
  5. ^ a b  One or more of the preceding sentences incorporates text from a publication now in the public domainChisholm, Hugh, ed. (1911). "Connellite" . Encyclopædia Britannica. 6 (11th ed.). Cambridge University Press. p. 963.