$350Median
1Sold (12 mo)
$350Last sale
Anorthite
10 in the gallery
Anorthite is a tectosilicate mineral in the plagioclase series with the formula CaAl2Si2O8. It typically forms in triclinic crystals and can occur as glassy to pearly surfaces with a vitreous to resinous lustre, often showing striated, eruption-like crystal faces. The color ranges from colorless to pale gray, sometimes with a faint brown or yellow tint in altered specimens, and it commonly occurs in clear to translucent crystals within igneous rocks and associated mineral assemblages. Notable specimens have come from Madagascar, Italy, and Japan, where hydrothermal and plutonic environments promote its crystallization, yielding well-formed crystals and crystal clusters.
- Formula
- Ca(Al2Si2O8)
- Rarity
- Common
- Stability
- Stable
- Collector interest
- Moderate Interest
- Classification notes
- Silicate minerals; tectosilicates; feldspar group (Aluminosilicate)
Where Anorthite is found
About Anorthite
Collectors value Anorthite for its clarity, angular habits, and classic plagioclase zoning displayed in some crystals. Specimens from notable localities exhibit clean terminations, diagnostic twinning, and pleasing luster, making them suitable for display as single crystals or as part of mineral cabinets. While common in some environments, well-formed, undamaged crystals with pristine faces remain highly desirable to enthusiasts seeking representative examples of plagioclase feldspar.
