Ilmenite
>
Ilmenite is a titanium-iron oxide mineral with the idealized formula FeTiO
₃. It is a weakly magnetic black or steel-gray solid. Ilmenite is the most important ore of titanium and the main source of titanium dioxide, which is used in paints,... Wikipedia
Birefringence: Strong; O: pinkish brown, E: dark brown (bireflectance)
Category: Oxide mineral
Cleavage: Absent; parting on, and
Color: Iron-black; gray with a brownish tint in reflected light
Crystal class: Rhombohedral (3); H-M symbol: (3)
Crystal habit: Granular to massive and lamellar exsolutions in hematite or magnetite
Crystal system: Trigonal