Adularia
Varietyof Orthoclase
Adularia is transparent orthoclase feldspar, classically from the Adula Alps. As a variety of Orthoclase, it shares that species' composition (K(AlSi3O8)), crystal structure, and hardness; the distinction is the appearance defined above.
Photos
About Orthoclase
Full reference data — crystallography, X-ray diffraction, and cited physical properties — is on the Orthoclase species page.
| Formula | K(AlSi3O8) |
|---|---|
| Hardness (Mohs) | 6-6.5 |
| Specific gravity | 2.5-2.62 |
| Density (calculated) | 2.555 |
| Crystal system | monoclinic |
| Color range | colorless, gray, green, red, white, yellow |
| Luster | vitreous |
| Streak | red |