10 FACTS ABOUT BROOKITE
July 9, 2024 by Elena Petrova
- Brookite is a rare collector’s mineral and one of the three main forms of titanium dioxide. Brookite, anatase, and rutile are polymorphous They share the same chemical formula but have different crystal systems and other gemological properties.
- Brookit Brookite is named in honor of Henry J. Brooke (1771-1857), an English mineralogistwho specialized in crystallography and discovered several new mineral species.
- A classic locality is Twll Maen Grisial, Prenteg, Wales, the type localityfor 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.
- Brookite is rarely faceted as a gemstone because it seldom occurs in sizes and shapes suitable for working. They are often incredibly thin (tabular) and typically dark or opaque. Also, Brookite is rather brittle, so a stone can break in the middle of the faceting process, rendering it useless.
- The refractive index of Brookite is one of the highest of any gem in the world at 2.58 which is higher than Diamond.
There are no known gem enhancements for brookites.
- Brookite only forms crystals but in various shapes: tabular, prismatic, pyramidal, and pseudo-hexagonal. Many are elongated with longitudinal striations.
- Transparent brookites are always under 1-2 carats. Larger brookite stones are opaque.
- Faceted brookite gemstones range from around $20 to $450 per carat.
- The important types of brookite to know are Arkansite and Platinum quartz or “dragonflies in quartz”. Arkansite is black, opaque variety of brookite named for its discovery in Arkansas, USA. Platinum quartz is quartz from Brazil with striking, "insectile" inclusionsof brookite blades and rutile needles.
Reference List:
www.mineralauctions.com
www.gemrockauctions.com
www.gemsociety.org
www.minerals.net/mineral/brookite.aspx
https://www.gemdat.org/gem
Check out our beautiful selection of Brookite crystals, from a variety of localities, as well as unique jewelry.
https://theglobalstone.com/search?type=product&q=brookite
