Brookite - TiO₂

Habit: Tabular and elongated, also prismatic, rarely tabular. Various shades of brown, to black. Opaque to translucent, transparent in thin fragments, Adamantine Luster.

Environment: An accessory mineral in fissures and veins of alpine type rocks in gneiss and schist with anatase, rutile, titanite, albite; also in contact metamorphic zones

Etymology: Named for Henry James Brooke (1771-1857), English crystallographer and mineralogist.