Anatase

Anatase

COLOR

Rather light grey. Visible pleochroism when the mineral is well crystallized. Takes a good polish.

REFLECTANCE

Rather low, but somewhat high for a transparent mineral. Higher than sphalerite, magnetite, ilmenite. Lower than hematite, slightly lower than rutile.

ANISOTROPISM

Rather strong but most often masked by a very bright diffuse internal reflections, light brown to yellowish or colorless, sometimes greenish or bluish.

TEXTURE

Sometimes as small euhedral crystals, but generally as powdery cryptocrystalline aggregates (leucoxene). The mineral is sometimes associated with hematite when replacing ilmenite (by oxidation). Often there are ghosts of titanomagnetite in which magnetite has been removed, ilmenite lamellae being replaced by anatase (leucoxene).

ASSOCIATED MINERALS

Ilmenite, magnetite, hematite, rutile.

CRITERIA OF DETERMINATION

Very similar to rutile. Compared to rutile, anatase has a slightly lower reflectance, lighter colored internal reflections and no twins. As a rule, anatase is the low-temperature form of TiO2, rutile the hight-temperature form.

Source

ATLAS OF ORE MINERALS (P. Picot and Z. Johan)