Crystals
Petrified wood
Fossil wood preserved by mineralization Commonly SiO2: opal, chalcedony, and quartz Growth rings, rays, vessels, and bark may survive Mohs about 6.5–7 when quartz-rich Agate veins and drusy cavities may...
Petrified wood
Fossil wood preserved by mineralization Commonly SiO2: opal, chalcedony, and quartz Growth rings, rays, vessels, and bark may survive Mohs about 6.5–7 when quartz-rich Agate veins and drusy cavities may...