Alstonite

Alstonite, also known as bromlite, is a low temperature hydrothermal mineral that is a rare double carbonate of calcium and barium with the formula BaCa(CO3)2, sometimes with some strontium. Barytocalcite and paralstonite have the same formula but different structures, so these three minerals are said to be trimorphous. Alstonite is triclinic but ...
Found on http://en.wikipedia.org/wiki/Alstonite

alstonite

a barium and calcium carbonate mineral, CaBa(CO3)2, with minor amounts of strontium. It is colourless or light gray or pink in appearance and is ...
Found on http://www.britannica.com/eb/a-z/a/53
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