Wiktionary
benstonite
n. (context mineral English) A trigonal-pyramidal mineral containing barium, calcium, carbon, magnesium, manganese, oxygen, and strontium.
Wikipedia
Benstonite
Benstonite is a mineral with formula BaCaMg(CO). Discovered in 1954, the mineral was described in 1961 and named after Orlando J. Benston (1901–1966).