Torbernite

Torbernite
Torbernite crystals from Mashamba West Mine, Kolwezi, Katanga Province, Democratic Republic of the Congo
General
CategoryPhosphate minerals
Formula
(repeating unit)
Cu[(UO2)(PO4)]2(H2O)12[1]
IMA symbolTor[2]
Strunz classification8.EB.05
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)[3]
Space groupI4/mmm[4]
Identification
Formula mass641 – 713 g/mol, depending the degree of water loss
ColorEmerald green to apple green[5]
Crystal habitTabular crystals; Foliated to earthy masses and encrustations
TwinningRare on [110]
Cleavage[001] Perfect; [100] Distinct[5]
FractureBrittle[5]
Mohs scale hardness2–2.5[5]
LusterVitreous; pearly[5]
StreakPale green
DiaphaneityTransparent to subtranslucent
Densitymeasured: 3.22; calculated: 3.264(1)[5]
Optical propertiesUniaxial (−)
Refractive indexnω = 1.590 – 1.592 nε = 1.581 – 1.582[3]
Birefringenceδ = 0.009 – 0.010[3]
PleochroismVisible
Melting pointDecomposes before
FusibilityDecomposes before
Other characteristics Radioactive and Poisonous

Torbernite, also known as chalcolite,[6] is a relatively common mineral with the chemical formula Cu[(UO2)(PO4)]2(H2O)12.[1] It is a radioactive, hydrated green copper uranyl phosphate, found in granites and other uranium-bearing deposits as a secondary mineral. The chemical formula of torbernite is similar to that of autunite in which a Cu2+ cation replaces a Ca2+ cation. Torbernite tends to dehydrate to metatorbernite with the sum formula Cu[(UO2)(PO4)]2(H2O)8.

  1. ^ a b Cite error: The named reference LocockBurns was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference Warr was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Webmineral was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference StrunzNickel was invoked but never defined (see the help page).
  5. ^ a b c d e f Cite error: The named reference Handbookofmineralogy was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Klockmann was invoked but never defined (see the help page).

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