Backscattered electron images of thin sections. (A) Pilotaxitic porous texture (holocrystalline, in which lath-shaped microlites are arranged in a glass-free felt mesh) of phonolite clast that consists of lath-shaped and zoned alkali feldspars (a-fs) with albite (ab) rims. (B) Similar texture of finer crystals as in A is shown for two adjacent clasts. (C) Mixture of albite and K-feldspar (kfs) within another clast surrounded by cryptocrystalline pumice. (D) Another variety of the pilotaxitic alkali feldspar porous groundmass enclosing phenocrysts of anorthoclase (an), globular crystals of calcite (cc), and minute grains of magnetite (mag).