n. (Min.) A variety of opal occuring in the cavities of volcanic tufa, in smooth and shining globular and botryoidal masses, having a pearly luster; -- so called from Fiora, in Ischia. [ 1913 Webster ]
n. [ Cf. F. diorite. See Diorism. ] (Min.) An igneous, crystalline in structure, consisting essentially of a triclinic feldspar and hornblende. It includes part of what was called greenstone. [ 1913 Webster ]
n. [ Cf. F. diorite. See Diorism. ] (Min.) An igneous, crystalline in structure, consisting essentially of a triclinic feldspar and hornblende. It includes part of what was called greenstone. [ 1913 Webster ]