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Labradorite

UNB-2018-0021Minerals » Tectosilicates

Description

Sample of a cut and polished Labradorite crystal that shows the characteristic play of colours. Labradorite is one of the Calcium-rich variety of the Plagioclase Feldspar Group that is characterized by the play of colours. Lustre is vitreous but can be pearly on cleavage and streak is white. Hardness is 6 and cleavage is good in two directions at nearly right angles and poor in a third direction. Twinning striations are often present on the cleavages. Labradorite (Plagioclase) usually occurs as lamellar, granular, disseminated or rosettes but can also form twin crystals.

Specifications

Object nameLabradorite
IDUNB-2018-0021
Legal statusPermanent collection
CategoryMineral
Classification
Mineral group:
Tectosilicates
Composition
  • CaB2Si2O8(OH,F)2
  • (Ca,Na2,K2)Al2Si4O12•6H2O
  • (Ca,Na)AlSi2O8
  • (Na2,K2)Al2Si4O12•2H2O
  • (Na,Ca)4(Al,Na)3Si9O24(Cl,CO3)2
  • (MAlO2)(SiO 2)x(H2O)y
  • (Na,K)AlSiO4
  • Na2Al2Si3O10·2H2O
  • KAlSi3O8
  • Na2Ca2Al6Si9O30·8H2O
  • K(AlSi2O6)
  • CaAl2Si4O12·4H2O
  • Pectolite NaCa2Si3O8(OH)2H2O with trace amounts of copper
  • (Ca,Na)(Al,Si)4O8
  • SiO2 with water inclusion
  • (Na,Ca)4-8Al6Si6(O,S)24(Cl,SO4)1-2
  • Na8(Al6Si6O24)Cl2
  • CaAl2Si3O10·3H2O
  • SiO2
  • (Cs,Na)2Al2Si4O12·2H2O
  • (Na, Ca)(Al, Si)AlSi2O8
  • KAlSi3O8
  • (Na,K)AlSi3O8
  • (Na,K)AlSi3O8
  • CaAl2Si2O8
  • SiO2
OriginUnknown
Pieces1
PartialNo
Measurements
  • 0.3cm x 4.8cm x 2.2cm

Publications

  • Chesterman, C.W. 1979. Audubon Society, Field Guide to North American Rocks and Minerals. Knopf.