Mineral Information and Data:

TiO2 [CNMNC approved formula]

Named in 1801 from the Greek, anatasis - "elongation" , for the greater length of the usual pyramid compared with other tetragonal minerals.

IMA status : Approved Species 1960 ()
(8th edition) :  
  (04) Simple Oxides
  (04.04) with a cation charge of 4+ (A++++ O2)
(10th edition) :
  (04) Oxides and Hydroxides
  (04.D) Metal:Oxygen = 1:2 and similar
  (04.DD) With medium-sized cations; frameworks 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 = 3.785 Ã…, c = 9.514 Ã…
Crystal Habit: Crystals steep pyramidal, often striated at right axis angles to c-axis; blunt pyramidal, tabular, prismatic
Twinning: rare on {112}
Color: Brown, deep blue, black; colourless, gray, green, blue
Diaphaneity: Transparent when lightly coloured to nearly opaque when dark coloured
Luster: Adamantine or metallic-adamantine
Hardness (Mohs): 5.5 - 6
Measured Density: 3.82 - 3.97 g/cm3
Cleavage: 2; {001} and {011} perfect
Tenacity: Brittle
Streak: Colorless, white, to pale yellow
Polymorphism and Series: Trimorphous with brookite and rutile.
Geologic Setting: Usually secondary, derived from other titanium-bearing minerals. In Alpine veins, derived from the enclosing gneisses or schists by hydrothermal solutions. In igneous and metamorphic rocks; in pegmatites; from a carbonatite. A common detrital mineral.
Mineral Association: Brookite, rutile, titanite, ilmenite, titanian magnetite, hematite, quartz
Synonyms/varieties: Dauphinite, hydrotitanite, octahedrite, wiserine
Other Properties: Gemstone Extremely Rare. BioMineral.
Comments: This mineral was first described in 1801 as the mineral octahedrite. Redefine and approved as anatase (IMA,1960).


Origin: Mid State quarry, Magnet Cove, Hot Spring Co.,
Arkansas, United States
Sample size: 8 x 7 x 2 cm, crystals to 1.5 mm
Photo: Tom Loomis


(zoom-in of above)


Origin: Lengenbach quarry, Binntal, Valais, Switzerland
Sample size: Microscopic image
Photo and Owner: Lou Perloff