Azurite

Azurite
Azurite from New Nevada lode, La Sal, Utah, USA
General
CategoryCarbonate mineral
Formula
(repeating unit)
Cu3(CO3)2(OH)2
IMA symbolAzu[1]
Strunz classification5.BA.05
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupP21/c
Unit cella = 5.01 Å, b = 5.85 Å
c = 10.35 Å; β = 92.43°; Z = 2
Identification
Formula mass344.67 g/mol
ColorAzure-blue, dark to pale blue; pale blue in transmitted light
Crystal habitMassive, prismatic, stalactitic, tabular
TwinningRare, twin planes {101}, {102} or {001}
CleavagePerfect on {011}, fair on {100}, poor on {110}
FractureConchoidal
Tenacitybrittle
Mohs scale hardness3.5 to 4
LusterVitreous
StreakLight blue
DiaphaneityTransparent to translucent
Specific gravity3.773 (measured), 3.78 (calculated)
Optical propertiesBiaxial (+)
Refractive indexnα = 1.730 nβ = 1.758 nγ = 1.838
Birefringenceδ = 0.108
PleochroismVisible shades of blue
2V angleMeasured: 68°, calculated: 64°
Dispersionrelatively weak
References[2][3][4]

Azurite is a soft, deep-blue copper mineral produced by weathering of copper ore deposits. During the early 19th century, it was also known as chessylite, after the type locality at Chessy-les-Mines near Lyon, France.[3] The mineral, a basic carbonate with the chemical formula Cu3(CO3)2(OH)2, has been known since ancient times, and was mentioned in Pliny the Elder's Natural History under the Greek name kuanos (κυανός: "deep blue," root of English cyan) and the Latin name caeruleum.[5] Copper (Cu2+) gives it its blue color.[6]

  1. ^ 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.
  2. ^ Handbook of Mineralogy
  3. ^ a b Mindat.org
  4. ^ Webmineral.com Webmineral Data
  5. ^ The Ancient Library: Smith, Dictionary of Greek and Roman Antiquities, p.321, right col., under BLUE Archived December 20, 2005, at the Wayback Machine
  6. ^ "Minerals Colored by Metal Ions". minerals.gps.caltech.edu. Retrieved 2023-03-01.

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