Devitrification of cast stones

Claim 1

IN A PROCESS OF FORMING A CAST STONE FROM A NATURAL STONE HAVING A COMPOSITION SUBSTANTIALLY SIMILAR TO THAT OF A STONE SELECTED FROM THE GROUP CONSISTING OF DIABASE, MELAPHHYRE, BASALT AND PORPHYRY, INCLUDING A DOMINANT MINERAL PHASE AND ALSO INCLUDING AT LEAST ONE ADDITIONAL MINERAL PHASE HAVING A RECRYSTALLIZATION TEMPERATURE LOWER THAN THE RECRYSTALLIZATION TEMPERATURE OF SAID DOMINANT MINERAL PHASE, THE STEPS OF CASTING SAID STONE, COOLING SAID CAST STONE BELOW THE RECRYSTALLIZATION TEMPERATURES OF SAID MINERAL PHASES, HEATING SAID STONE TO THE RECRYSTALLIZATION TEMPERATURE OF SAILD DOMINANT MINERAL PHASE, MAINTAINING SAID STONE AT SAID RECRYSTALLIZATION TEMPERATURE OF SAID DOMINANT MINERAL PHASE UNTIL SUBSTANTIALLY ALL OF SAID DOMINANT MINERAL PHASE HAS BEEN RECRYSTALLIZED, COOLING SAID STONE BELOW THE RECRYSTALLIZATION TEMPERATURE OF SAID ADDITIONAL MINERAL PHASE, HEATING SAID STONE TO THE RECRYSTALLIZATION TEMPERATURE OF SAID ADDITIONAL MINERAL PHASE, AND MAINTAINING SAID STONE AT SAID RECRYSTALLIZATION TEMPERATURE OF SAID ADDITIONAL MINERAL PHASE UNTIL SUBSTANTIALLY ALL OF SAID ADDITIONAL MINERAL PHASE HAS BEEN RECRYSTALLIZED, WHEREBY A DEVITRIFIED CAST BODY IS FORMED OF SAID NATURAL STONE.