triclinic Tectosilicates
Amazonite
Formula KAlSi3O8
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}
Quick Facts
Hardness
6.0
Specific Gravity
2.56
Refractive Index
1.522
Optical Character
Biaxial -
Physical Properties
- Crystal System
- triclinic
- Hardness (Mohs)
- 6.0
- Specific Gravity
- 2.56
- Cleavage
- Perfect {001} and {010} at approximately 90 degrees
- Fracture
- Uneven
- Lustre
- Vitreous
Optical Properties
- Refractive Index
- 1.522
- Birefringence
- 0.008
- Optical Character
- Biaxial -
- Dispersion
- 0.012
- Pleochroism
- None
Characteristics
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
Related Minerals
Other minerals in the triclinic system
