Ganophyllite
Ganophyllite's name came from the Greek words leaf (φύλλον) and luster (γανωμα).[1] It got its name from Axel Hamberg in 1890. It is a member of Ganophyllite group, among with eggletonite and tamaite. It has a barely detectable potassium radioactivity. The formula includes potassium (K) if it is ganophyllite, eggletonite includes natrium (Na), and tamaite includes calcium (Ca) in their formula.
| Ganophyllite | |
|---|---|
| General | |
| Category | Mineral |
| Formula (repeating unit) | (K,Na,Ca)2Mn8(Si,Al)12(O,OH)32 · 8H2O |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) |
| Space group | A2/a |
| Identification | |
| Color | Brownish yellow to cinnamon brown |
| Crystal habit | Foliated micaceous |
| Cleavage | {???}Perfect |
| Fracture | Brittle |
| Mohs scale hardness | 4 - 4.5 |
| Luster | Vitreous |
| Streak | Brownish yellow |
| Diaphaneity | Transparent to transculent |
| Specific gravity | 2.84 |
| Density | 2.84 |
| Optical properties | Biaxial(-) |
| Refractive index | nα = 1.537 nβ = 1.611 nγ = 1.613 |
| Birefringence | δ = 0.076 |
| Dispersion | Weak |
| Ultraviolet fluorescence | Non-fluorescent |
| Common impurities | Fe, Zn, Pb, Ca, Ba |
| Other characteristics |  Radioactive 3.87% (K) |
References
- "Ganophyllite Mineral Data". webmineral.com. Retrieved 22 January 2021.
External links
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