Cassiterite

Cassiterite
Cassiterite with muscovite, from Xuebaoding, Huya, Pingwu, Mianyang, Sichuan, China (size: 100 x 95 mm, 1128 g)
General
CategoryOxide minerals
Formula
(repeating unit)
SnO2
IMA symbolCst[1]
Strunz classification4.DB.05
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H-M symbol: (4/m 2/m 2/m)
Space groupP42/mnm
Unit cella = 4.7382(4) Å,
c = 3.1871(1) Å; Z = 2
Identification
ColorBlack, brownish black, reddish brown, brown, red, yellow, gray, white; rarely colorless
Crystal habitPyramidic, prismatic, radially fibrous botryoidal crusts and concretionary masses; coarse to fine granular, massive
TwinningVery common on {011}, as contact and penetration twins, geniculated; lamellar
Cleavage{100} imperfect, {110} indistinct; partings on {111} or {011}
FractureSubconchoidal to uneven
TenacityBrittle
Mohs scale hardness6–7
LusterAdamantine to adamantine metallic, splendent; may be greasy on fractures
StreakWhite to brownish
DiaphaneityTransparent when light colored, dark material nearly opaque; commonly zoned
Specific gravity6.98–7.1
Optical propertiesUniaxial (+)
Refractive indexnω = 1.990–2.010 nε = 2.093–2.100
Birefringenceδ = 0.103
PleochroismPleochroic haloes have been observed. Dichroic in yellow, green, red, brown, usually weak, or absent, but strong at times
Fusibilityinfusible
Solubilityinsoluble
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.

  1. ^ 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.
  2. ^ Mineralienatlas
  3. ^ 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.
  4. ^ Cassiterite, Mindat.org
  5. ^ Webmineral
  6. ^ 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.