Image: <bdi><a href="https://www.wikidata.org/wiki/Q126871366" class="extiw" title="d:Q126871366"><span title="photographer from the United States">Nessa Eull</span></a></bdi> (CC0)
orthorhombicuncommonOxides
Brookite
TiO2
Brookite forms dark, tabular to platy crystals, often exhibiting a submetallic to adamantine luster. It is a polymorph of rutile and anatase, sharing the same chemical composition.
Brookite Physical Properties
Mohs Hardness
5.5Crystal System
orthorhombicLuster
vitreousStreak Color
yellowish-brown to black, or colorlessCleavage
distinct on {120}, indistinct on {001}Fracture
subconchoidal to irregularSpecific Gravity
4.08Colors
reddish-brown, dark brown, black, yellowish, blueTransparency
opaque to translucentType Locality
Magnet Cove, Hot Spring County, Arkansas, USAMineral Group
OxidesUses
collector's mineral, minor source of titaniumAssociated Minerals
rutile, anatase, quartz, adularia, chloriteRarity
uncommonGeological Context
Brookite typically forms in hydrothermal veins, alpine clefts, or as an alteration product in metamorphic and igneous rocks, stable at lower temperatures than its polymorph rutile.
