Recent studies have demonstrated that the flaking characteristics of certain siliceous stone materials are enhanced by carefully controlled annealing and that intentional annealing was indeed practiced by prehistoric Native Americans. A note of caution is extended here to investigators who might extend evidence for thermally altered siliceous stone from a site to interpretations that intentional annealing was practiced at the site. The use of fire in quarrying has a long history throughout the world, and much heat-treated material from sites may have been thermally altered unintentionally, the result of quarrying practices.
