Laser marking process for vitrification of bricks and other vitrescent objects

A method of marking a surface of a vitrescent object by vitrifying said surface utilizing a laser marking system comprising:

• providing a means for producing a continuous wave laser beam selected from the group consisting of a Nd:Yag laser and a CO.sub.2 laser having a laser beam width and a laser beam intensity, said laser beam producing means operating in a power range of 60-250 watts and including a collimator and a lens;
• setting said collimator to produce a beam expansion within the range of about 1.6x-1.9x whereby an optimum width laser beam is produced having a laser beam intensity in the range of about 1.6.times.10.sup.5 -1.4.times.10.sup.6 watts/cm.sup.2 for marking of said vitrescent object;
• providing a means for steering said laser beam along a path, said steering means being configured for localized vitrification of a vitrescent object placed in said path of the laser beam, said steering means being computer controlled for producing lettering and graphical patterns on said vitrescent object;
• placing said vitrescent object in a working area in said path of said beam;
• programming said steering means to produce a desired image on said vitrescent object;
• and
• activating said beam and steering means to produce said desired image on said vitrescent object to thereby vitrify a portion of the surface thereof.