tritomite
noun
trit·o·mite
ˈtritəˌmīt
plural -s
: a complex fluosilicate chiefly of calcium, thorium, cerium, yttrium, and containing boron
Word History
Etymology
German tritomit, from Greek tritomos thrice cut + German -it -ite; from the fact that the crystals leave trihedral cavities in the gangue