Wiktionary
n. (context mineral English) A monoclinic barium calcium carbonate mineral.
Wikipedia
Barytocalcite is an anhydrous barium calcium carbonate mineral with the chemical formula Ba Ca( C O). It is trimorphous with alstonite and paralstonite, that is to say the three minerals have the same formula but different structures. Baryte and quartz pseudomorphs after barytocalcite have been observed.
Barytocalcite crystallizes in the monoclinic crystal system, typically as massive to druzy accumulations of transparent white to yellow to grey aggregates of slender prismatic crystals. It has a Mohs hardness of 4 and a specific gravity of 3.64 to 3.71.
It was first described in 1824 for an occurrence in the Blagill Mine in North Pennines, Cumbria ( Cumberland), England, and named for its composition.