Papagoite

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Papagoite
Papagoite-k-152b.jpg
Crystalline papagoite from Namibia (size: 5.9 x 3.3 x 2.1 cm)
General
CategoryCyclosilicate
Formula
(repeating unit)
CaCuAlSi2O6(OH)3
Strunz classification9.CE.05
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Unit cella = 12.92 Å, b = 11.49 Å,
c = 4.69 Å; β = 100.81°; Z = 4
Identification
ColorDark blue crystals, light blue when massive
Crystal habitMassive; cryptocrystalline, forming flat elongated crystals
CleavageImperfect in one direction
FractureBrittle
Mohs scale hardness5-5.5
LusterVitreous to dull
StreakLight blue
Specific gravity3.25
Optical propertiesBiaxial (-)
Refractive indexnα = 1.607 nβ = 1.641 nγ = 1.672
Birefringenceδ = 0.065
PleochroismTrichroic
2V angleMeasured: 78°
References[1][2][3][4]

Papagoite is a rare cyclosilicate mineral. Chemically, it is a calcium copper aluminium silicate hydroxide, found as a secondary mineral on slip surfaces and in altered granodiorite veins, either in massive form or as microscopic crystals that may form spherical aggregates. Its chemical formula is CaCuAlSi2O6(OH)3.

It was discovered in 1960 in Ajo, Arizona, US, and was named after the Sand Papago peoples (now named Hia C-ed O'odham) that inhabit the area.[4] This location is the only papagoite source within the United States, while worldwide it is also found in South Africa and Namibia. It is associated with aurichalcite, shattuckite, ajoite and baryte in Arizona, and with quartz, native copper and ajoite in South Africa.[4] Its bright blue color is the mineral's most notable characteristic.

It is used as a gemstone.[5]

References[edit]

  1. ^ Mineralienatlas
  2. ^ MinDat
  3. ^ Webmineral
  4. ^ a b c Handbook of Mineralogy
  5. ^ Dictionary of Gems and Gemology By Mohsen Manutchehr-Danai p.352


Papagoite with conichalcite, from Ajo, Arizona.
Papagoite and native copper inclusions on a quartz crystal from Limpopo Province, South Africa (size 7.0 x 3.7 x 2.6 cm)