pinakiolite
noun
pi·nak·i·o·lite
pə̇ˈnakēəˌlīt
plural -s
: a magnesium and manganese borate Mg3Mn3B2O10 occurring in small black tabular crystals
Word History
Etymology
German pinakiolith, from Greek pinakion small tablet (diminutive of pinak-, pinax board, tablet) + German -lith -lite