Amazonite crystal structure
triclinic Tectosilicates

Amazonite

KAlSi3O8

Quick Facts

Hardness
6.0
Specific Gravity
2.56
Refractive Index
1.522
Optical Character
Biaxial -

Crystal Structure

#! Species: Amazonite (Microcline Feldspar) #! System: Triclinic (-1) #! Habit: Prismatic with Baveno twinning and lead-green colour triclinic[-1]:{010}@1.0 + {001}@0.9 + {110}@0.7[colour:green] | twin(baveno)
triclinic
-1
{010} {001} {110}

Physical Properties

Crystal Systemtriclinic
Hardness (Mohs)6.0
Specific Gravity2.56
CleavagePerfect {001} and {010} at approximately 90 degrees
FractureUneven
LustreVitreous

Optical Properties

Refractive Index1.522
Birefringence0.008
Optical CharacterBiaxial -
Dispersion0.012
PleochroismNone

Colours

GreenBlue-greenTurquoise blueWith white streaks (perthite)

Localities

Colorado (USA - Pikes Peak, Crystal Peak)BrazilRussia (Kola Peninsula, Urals)MadagascarIndiaNamibia

Crystal Forms

pinacoidprismBaveno twins (common)

Notes

Color from Pb+H2O color centers, not copper; often perthitic with white albite streaks

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#! Species: Amazonite (Microcline Feldspar) #! System: Triclinic (-1) #! Habit: Prismatic with Baveno twinning and lead-green colour triclinic[-1]:{010}@1.0 + {001}@0.9 + {110}@0.7[colour:green] | twin(baveno)