 |
|
|
Brookite is one of the three main forms of titanium dioxide. It forms distinct and unique crystals, and is often associated with the two other minerals it is polymorphous with, Rutile and Anatase. Brookite almost always forms together with Quartz, and is occasionally entirely included within a Quartz crystal. Brookite is named in honor of Henry J. Brooke (1771-1857), an English mineralogist who specialized in crystallography and discovered several new mineral species. |
|
|
Chemical Formula |
TiO2 |
|
Composition |
Titanium dioxide |
|
Color |
Reddish-brown, brown, yellow-brown, yellow-orange, greenish-gray, black. Often has lighter and darker color zones, or a black zone running through the center of a crystal. |
|
Streak |
Light yellow-gray to nearly white |
|
Hardness |
5.5 - 6 |
|
Crystal System |
Orthorhombic |
|
|
|
Crystal Forms
and Aggregates |
In characteristic flattened tabular or prismatic crystals with elongated pointed termination. These crystals may be standalone, or in platy aggregates or bladed. Crystals may also be bipyramidal or pseudohexagonal, as well as in equant stubby crystals. Crystals are usually microscopic to very small, except at a few localities where they occur in larger crystals. Crystals are usually striated.
|
|
Transparency |
Transparent to translucent |
|
Specific Gravity |
4.1 - 4.2 |
|
Luster |
Adamantine, submetallic |
|
Cleavage |
3,2 |
|
Fracture |
Uneven, subconchoidal |
|
Tenacity |
Brittle |
|
In Group |
Oxides; Simple Oxides |
|
Striking Features |
Crystal habits and luster |
| Environment |
In low temperature alpine Quartz veins and cavities in
metamorphosed schists and gneiss, in hydrothermal vein deposits, and in placer
deposits.
|
| Rock Type |
Metamorphic |
|
Popularity (1-4)
|
3 |
|
Prevalence (1-3)
|
3 |
|
Demand (1-3) |
2 |
|
|
 |
|
|
|
|
- Brookite from Magnet Cove, Arkansas, with a characteristic color and shape.
|
Brookite is a rare collectors mineral and is desired by collectors, especially good crystals.
|
A classic British locality is Twll Maen Grisial, Prenteg, Wales, the type locality for Brookite that was once well-known for producing large Brookite crystals. Other European localities include Le Trient, Wallis, Switzerland; the Reuss Valley, Uri, Switzerland; and Mt. Bregaceto, Borzonasca, Italy.
Exceptionally large and beautifully colored Brookite crystals come from Balochistan, Pakistan, at Taftan, Dalbandin, and Kharan. In Russia, well-formed crystals come from Siberia at the Dodo and Puiva Mine, both in Saranpaul. Large crude crystals have been found at Fitampito, Iralamavory, Madagascar.
In the U.S., the only significant Brookite locality is Magnet Cove, Hot Springs Co., Arkansas, which is famous for its large black and often lustrous crystals.
|
Topaz - Harder, not usually in flattened crystals.
|
|
|
|
|
|
|
|
Have a question about Brookite? Visit our Q&A Community and ask the experts!
|
|
|
|
Let us know how we can update this page
(Click for more details)
|
|
We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.
|
 |
| |
|
|
|
|
|
|
|
