Sursassite
Sursassite is a sorosilicate mineral. It was first discovered in 1926.[4] It was first found in the Sursass (Oberhalbstein), a district of Graubünden, Switzerland. It is generally found in deposits of metamorphosed manganese.[5]
| Sursassite | |
|---|---|
|  | |
| General | |
| Category | Sorosilicate | 
| Formula (repeating unit) | Mn2+2Al3(SiO4)(Si2O7)(OH)3 | 
| IMA symbol | Ss[1] | 
| Strunz classification | 9.BG.15 | 
| Crystal system | Monoclinic | 
| Crystal class | Prismatic (2/m) (same H-M symbol) | 
| Space group | P21/m | 
| Identification | |
| Color | Red-brown to copper-red | 
| Crystal habit | Botryoidal | 
| Cleavage | [101] Distinct | 
| Mohs scale hardness | 3 | 
| Luster | Silky, Dull | 
| Streak | yellow-brown | 
| Diaphaneity | Translucent | 
| Density | 3.256 | 
| Optical properties | Biaxial | 
| Refractive index | 1.73 to 1.76 | 
| Birefringence | 0.030 | 
| Pleochroism | Strong; X = Z = colorless to pale yellow; Y = deep golden brown. | 
| Dispersion | r > v | 
| References | [2][3] | 
Notes
    
- Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- Pierre Perroud. "Sursassite". Athena Mineralogy: Mineral Data.
- Sursassite details from Handbook of Mineralogy
- Schweizerische mineralogische und petrographische Mitteilungen (1926), 6, 376-380.
- Barthelmy, Dave. "Sursassite Mineral Data". WebMineral. Retrieved 2009-03-17.
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