triclinic Tectosilicates
Andesine (Tabular)
(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 Systemtriclinic
Hardness (Mohs)6.0
Specific Gravity2.65
CleavagePerfect {001} and good {010}
FractureUneven to conchoidal
LustreVitreous
Optical Properties
Refractive Index1.543
Birefringence0.008
Optical CharacterBiaxial -
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
