Mineral Information and Data:

SnO2 [CNMNC approved formula]

Named from the Greek for tin.

IMA status : Valid species (Pre-IMA 1832) Grandfathered
(8th edition) :  (This Dana# Added)
  (04) Simple Oxides
  (04.04) with a cation charge of 4+ (A++++ O2)
  (04.04.01) Rutile group (Tetragonal: P4/mnm)
(10th edition) :
  (04) Oxides and Hydroxides
  (04.D) Metal:Oxygen = 1:2 and similar
  (04.DB) With medium-sized cations; chains of edge-sharing octahedra
Crystal system: Tetragonal System
Point group (H-M): 4/mmm (or 4/m 2/m 2/m) — ditetragonal-dipyramidal
Unit cell: a = 4.738 Ǻ, c = 3.188 Ǻ
Crystal Habit: Crystals short prismatic, sometimes slender prismatic or pyramidal; granular, botryoidal of reniform masses
Twinning: Very common on {011}, contact, penetration, geniculated, or lamellar
Color: Brown to brownish black, black, colourless, gray, yellowish
Diaphaneity: Transparent, Translucent, Opaque
Luster: Adamantine, Greasy, Sub-Metallic
Hardness (Mohs): 6 to 7
Measured Density: 6.99 g/cm3
Cleavage: 4; {100} imperfect, {110} indistinct, {111} and {011} parting
Tenacity: Brittle
Fracture: Subconchoidal to uneven
Streak: White, grayish, brown
Geologic Setting: In medium- to high-temperature hydrothermal veins and greisen, in granite,
granite pegmatite, rhyolite; rarely in contact metamorphic deposits; in large alluvial placers.
Mineral Association: Quartz, muscovite, wolframite, tourmaline, topaz, fluorite, scheelite, lepidolite, arsenopyrite, bismuth, molybdenite
Ore deposits: Primary mineral ore of tin.
Synonyms/varieties: Ainalite (Ta-rich variety), wood tin (colloform variety), stannite, varlamoffite (Fe3+ -rich variety)
Other Properties: Gemstone Rare.


Origin: St. Agnes, Cornwall, England
Sample size: 7 x 4 x 2 cm, fair dark crystals to 8 mm
Photo: Tom Loomis


(zoom-in of above)


3 mm black euhedral crystals in lepidolite matrix. During the so-called "Tin Boom" in the Black Hills in the late 1800's this stuff was called "Pepper Ore".
Origin: Etta mine, Custer Co., South Dakota, United States
Sample size: 4 x 2 x 2 cm
Photo: Tom Loomis


(zoom-in of above)