Crystals of anatase are often found with a well-developed pyramidal or tabular habit. They can be blue, red, brown, or colorless, although examples of orange, dark red, reddish-brown, and bluish green also occur. Its pleochroism is weak but more distinctive in the intensely colored specimens. The blue coloration of anatase may be due to the presence of Ti3+ and Ti2+.
Anatase is a metastable mineral form of titanium dioxide. It may change to rutile under specific thermodynamic conditions. Anatase is one of the five forms of titanium dioxide found in nature. The others are Akaogiite, Brookite, Riesite, and Rutile.
It is usually found isolated as small, sharply developed crystals. Like its thermodynamically stable cousin, rutile, it crystallizes tetragonally. The mineral is mainly encountered as a black solid, although pure material is colorless or white. Some crystals may appear opaque because of total reflection.
Due to its potential application as a semiconductor, anatase has been grown synthetically.
