triclinic Tectosilicates
Andesine (Tabular)
Formula (Ca,Na)(Al,Si)4O8
Crystal Structure
#! Species: Andesine
#! System: Triclinic (-1)
#! Habit: Tabular on {010}
triclinic[-1]:{010}@1.0 + {001}@0.8 + {110}@0.6
triclinic
-1
{010} {010} {001} {110}
Quick Facts
Hardness
6.0
Specific Gravity
2.65
Refractive Index
1.543
Optical Character
Biaxial -
Physical Properties
- Crystal System
- triclinic
- Hardness (Mohs)
- 6.0
- Specific Gravity
- 2.65
- Cleavage
- Perfect {001} and good {010}
- Fracture
- Uneven to conchoidal
- Lustre
- Vitreous
Optical Properties
- Refractive Index
- 1.543
- Birefringence
- 0.008
- Optical Character
- Biaxial -
Characteristics
Colours
RedOrange-redGreenYellow-green
Localities
Tibet (China)MongoliaOregon (USA)Democratic Republic of Congo
Common Inclusions
Twin lamellaeSchiller inclusions
Known Treatments
Copper diffusion (controversial, for red colour)
Crystal Forms
pinacoidprism
Notes
Red andesine origin and treatment status frequently debated in gem trade
Related Minerals
Other minerals in the triclinic system
