Investigation of the action of continuous CO2 laser radiation on quartz-group minerals and quartz-bearing rocks

A study was made of the effects of focused 200–W CO₂ laser radiation (power density 1X10⁵ W/cm²) on rock crystal, agate, opal, sandstone, and quartzite. The two main damage mechanisms were considered: One was the brittle fracture due to phase transitions in a quartz and the other was the thermal decompositon accompanied by low-temperature sublimation of water and silica. The latter process was followed by further heating of a jet of matter and formation of a melted surface zone on opal and sandstone, and partly on agate. In all cases the absorption of radiation and heating were due to the Si–O valence vibrations.