Uneven
ConchoidalAnthony et al, Handbook of mineralogy (2001), ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle, Conchoidal
MgB 3O 3(OH) 5 · 5H 2OMichael OâDonoghue , Gems, Sixth Edition (2006)
Al 4(Ta,Nb) 3(O,OH,F) 14Ulrich Henn and Claudio C.