Chambersite Info

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General

Chambersite (Mn2+3B7O13Cl) is a very rare manganese analogue of boracite (Mg3B7O13Cl). It contains manganese, boron, oxygen and chlorine. The purple, tetragonal crystals are small, usually up to 1 cm. They are found in brine residues from extraction wells in salt domes, associated with anhydrite, gypsum, and halite. Chambersite was named after the location where it was first discovered: Chambers County, Texas, USA.
It is hard enough (Mohs scale 7) to be used in jewelry but still rather unknown to the public.

History

Chambersite crystals were discovered in 1957 in brine returns from a gas storage well (storage well no. 1 / Texas Natural Gasoline Corporation) in the Barber's Hill salt dome / Chambers County / Texas / USA. The crystals of the first discovery were described in 1962 by R.M. Honea and F.R. Beck. Description of new finds in China by D. Fan, P. Yang, R. Wang, in 1999.

Deposits

Salt Dome
Salt Dome *
First chambersite crystals originated from 700 - 800 m deep extraction wells in the Barber's Hill salt dome in Mont Belvieu / Chambers County / Texas / USA. The salt is appr. 100 - 150 million years old.
Other deposits:
Venice Salt Dome / Lake Judge Perez (Lake Hermitage) / Venice / Plaquemines Parish / Lousiana / USA,
Darrow Salt Dome / Donaldsonville / Ascension Parish / Louisiana / USA,
Tianjin City / China, Zhongxinchun B-Mn Deposit / Pinggu Distr. / Beijing / China, and Dongshiuchang B-Mn Deposit / Zunhua Distr. / Tangshan / China,
Truskavets / Ukraine.

* Photo by kind permission of © Doug Oliver.

Color and Quality

Chambersite Mineral
Very good Chambersite *
The color varies from very light (near colorless) to very dark purple, sometimes brownish or grey. Long exposure to sunlight deepens the color. Chambersite crystals are usually heavily included. Larger (> 0.3 cm !) crystals without inclusions are nearly impossible to find. A very valuable chambersite should have only a few inclusions, should be transparent, and should show a not too dark purple color. Treatments resp. enhancements are not known for chambersite. Faceted stones usually show a triangular cut.

Prices vary strongly, from about 20 to 200 USD for 0.5 cm rough crystals, and about 200 USD for 0.2 ct faceted stones. Until now good stones are only available from U.S. deposits.

* Photo by kind permission of © www.kox-gems.com.


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