allemontite

[ al-uh-mon-tahyt ]
/ ˌæl əˈmɒn taɪt /

noun

a white to gray, brittle mineral, antimony arsenide, AsSb, occurring in reniform masses: formerly used as an ore of arsenic.

Origin of allemontite

1830–40; named after Allemont (place in France where found); see -ite1