spectacle (1) Area (1) Forms (1) Hydrothermal alteration (1) Area (1) Zeolites (1) White (1) Volcanic ash, tuff, etc (1) Veins (1) Variations (1) Silica (1) Rocks (1) Quartz (1) Opals (1) Green (1) Fluid inclusions (1) Calcite (1) Structure (1) Number (1) silice (1) vert (1)