BROOKITE TiO2 Orthorhombic
Description: Brookite is a relatively uncommon mineral found as an accessory in a number of igneous and metamorphic rocks including granites, syenites, gneisses, and schists. It may also be formed in hydrothermal veins. It is resistant enough to weathering to survive as a heavy mineral in sediments.
MARATHON COUNTY: Brookite is widespread as black, green, yellow and light brown stubby to platy crystals averaging 1 mm. long in vugs in granite pegmatites of the Wausau pluton. These are exposed in the "rotten granite" quarries such as the Wimmer #3 pit south of Rib Mountain (Falster, 1987; Buchholz 1999b., Falster et. al., 2000).
- Reported with anatase from a quarry on Mosinee Hill, NW sec. 26 T.26N. R.7E. (Lloyd Brown, pers. comm.)
WOOD COUNTY: Brookite is rarely found as tan micro-crystals associated with anatase and rutile at the Tork and Haessley Quarries near Wisconsin Rapids (Buchholz, 1996).
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