petalite
/ˈpɛtəlʌɪt/ /ˈpɛt(ə)lʌɪt/Mineralogy
noun
A rare mineral of the monoclinic crystal system consisting of lithium aluminosilicate, LiAlSi4O10, which occurs as greyish to black metallic masses with a leaflike cleavage and is used in some ceramics.
Origin
Early 19th century. From ancient Greek πέταλον leaf + -ite, after German Petalit.