Figure F75. Angular fragment of volcanic rock with stretched vesicles within a quartz-pyrite matrix. Pyrite and chalcopyrite fill some vesicles along the edge of the fragment (Sample 193-1189A-12R-1 [Piece 16, 122-125 cm]; width of view = 1.38 mm. Photomicrograph ID# 1189A_18; thin section 42.).