| Cassiterite | |
|---|---|
 Cassiterite with muscovite, from Xuebaoding, Huya, Pingwu, Mianyang, Sichuan, China (size: 100 x 95 mm, 1128 g) | |
| General | |
| Category | Oxide minerals |
| Formula (repeating unit) | SnO2 |
| IMA symbol | Cst[1] |
| Strunz classification | 4.DB.05 |
| Crystal system | Tetragonal |
| Crystal class | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
| Space group | P42/mnm |
| Unit cell | a = 4.7382(4) Å, c = 3.1871(1) Å; Z = 2 |
| Identification | |
| Color | Black, brownish black, reddish brown, brown, red, yellow, gray, white; rarely colorless |
| Crystal habit | Pyramidic, prismatic, radially fibrous botryoidal crusts and concretionary masses; coarse to fine granular, massive |
| Twinning | Very common on {011}, as contact and penetration twins, geniculated; lamellar |
| Cleavage | {100} imperfect, {110} indistinct; partings on {111} or {011} |
| Fracture | Subconchoidal to uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 6–7 |
| Luster | Adamantine to adamantine metallic, splendent; may be greasy on fractures |
| Streak | White to brownish |
| Diaphaneity | Transparent when light colored, dark material nearly opaque; commonly zoned |
| Specific gravity | 6.98–7.1 |
| Optical properties | Uniaxial (+) |
| Refractive index | nω = 1.990–2.010 nε = 2.093–2.100 |
| Birefringence | δ = 0.103 |
| Pleochroism | Pleochroic haloes have been observed. Dichroic in yellow, green, red, brown, usually weak, or absent, but strong at times |
| Fusibility | infusible |
| Solubility | insoluble |
| References | [2][3][4][5][6] |
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains the most important source of tin today.
- ^ 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.
- ^ Mineralienatlas
- ^ Anthony, John W.; Bideaux, Richard A.; Bladh, Kenneth W.; Nichols, Monte C. (2005). "Cassiterite" (PDF). Handbook of Mineralogy. Mineral Data Publishing. Retrieved 19 June 2022.
- ^ Cassiterite, Mindat.org
- ^ Webmineral
- ^ Hurlbut, Cornelius S.; Klein, Cornelis (1985). Manual of Mineralogy (20th ed.). New York: John Wiley and Sons. pp. 306–307. ISBN 0-471-80580-7.