Brookite
Mineral TiO2
Also called Arkansite
About it
Thin brown plates, often with a dark hourglass zone, from the same Alpine clefts as anatase. Magnet Cove, Arkansas, gives thick black crystals once called arkansite.
- Type
- Mineral
- Group
- Oxide (TiO2 polymorph)
- Formula
- TiO2
- Hardness (Mohs)
- 5.5–6
- Specific gravity
- 4.08–4.18
- Streak
- white to yellowish white
- Lustre
- adamantine (diamond-like), submetallic
- Crystal system
- Orthorhombic
- Colours
- red-brown, yellow-brown, dark brown, black
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- poor; subconchoidal to uneven fracture
Typical values: real specimens vary. For more, see mindat.org.