Mineral · Rutile group
Brookite
TiO2
Brookite is the orthorhombic TiO2 polymorph, forming thin, striated, tabular brown crystals with hourglass zoning in Alpine clefts, Magnet Cove (Arkansas) and Pakistan's Zagi Mountain, where superb crystals on quartz are found. It is rarer than rutile and anatase and correspondingly more expensive. Zagi brookite has flooded the market since 2005 and is genuine.
| Formula | TiO2 |
|---|---|
| IMA status | grandfathered |
| Crystal system | Orthorhombic |
| Mohs hardness | 5.5–6 |
| Group | Rutile group |
| Type locality | Snowdon, Wales |
| Streak | White to yellowish |
| Specific gravity | 4.1 |
| Reference list | IMA List of Minerals (RRUFF) — verify formula and status against the current list |
Elsewhere
Cite this article
Stratum Study. "Brookite" (Mineral). Stratum Study pack 2026.09, as of 2026-09-19. https://stratum.black/study/minerals/brookite. Accessed 2026-09-20.
@misc{stratum-brookite,
title = {Brookite},
author = {{Stratum Study}},
howpublished = {\url{https://stratum.black/study/minerals/brookite}},
year = {2026},
note = {Mineral article, Stratum Study pack 2026.09, as of 2026-09-19; sources: stratum, wikidata, commons. Accessed 2026-09-20.}
} Citations carry the pack version and the article's as-of date so they resolve to the same text later. The facts themselves belong to the sources listed below; cite those for the science.