He has also found that quartzite spalls very easily, while a rock like basalt does not spall, but melts. The Cold Spring Granite Company plant in Cold Spring, Minnesota, uses a flame to produce surfaces on some of the tiles they sell. Nearly all the quartz, which has a high thermal expansivity compared to the other minerals in granite, is spalled from the surface. To rid the spalled material from flamed surfaces, a stream of water is sprayed away from the flame. When the spalled material is not removed, it melts and forms a glaze on the surface.
Several quarries use a fuel oil and compressed air torch to quarry large blocks of granite.
The rock surfaces on Inca stones are similar to those that have been thermally disaggregated. Indeed, some of. the slick surfaces on the Inca building stones are glazed, so it becomes apparent that the Incas must have used thermal disaggregation. The fire used for this sacrifice had to be fresh or, as they said, given to them by the hand of the Sun. For this, they took a large bracelet, belonging to the high priest, and similar in form to that usually worn on their left wrists by the Incas. The central motif of this bracelet was a very carefully polished concavity as big as half an orange.