chambersite

Chambersite is a manganese borate mineral with formula . It is a member of the borate mineral series that includes other minerals such as ericaite () and boracite (). When chambersite was first discovered, it was the second chemical analogue of boracite to be found in nature. It was discovered as a mineral at Barber's Hill salt dome in Texas in 1957 and in 1971 at the Dongshuichang deposit in Jixian, Tianjin, China. Chambersite occurs associated with the evaporite minerals halite, anhydrite, and gypsum.

==Chemical and physical properties== When chambersite was first discovered in Barber's Hill, the dominant form was the positive tetrahedron, but single morphological twinned crystal was found with interpenetrating tetrahedrons with the twinning axis. The ore discovered in China had formed in high grades that are spindle and granular that form micritic aggregates because the boron present is very pure and in low grades that had formed spheroids that are radially oriented. When chambersite in China was compared it had the same chemical oxide ratio as the samples found in Barber's Hill.