Figure F73. Color close-up photograph of Sample 183-1139A-70R-4 (Piece 5A, 94-104 cm). Highly to completely altered sanidine-phyric trachyandesite. Light gray rock with siderite-filled vesicles is overprinted by white (siderite and quartz) alteration. Quartz, siderite, and hematite(?) vein has prominent oxidation halo that cuts across the white alteration zone.