Catamount Glassware was founded in the late 1970's by Alain Karyo, an artist and student of modern architecture. His designs combine form and function, two essential elements in creating practical, easily handled cookware. Made from borosilicate glass, the Catamount products were originally developed for use in scientific laboratories. These crystal clear Catamount products are flame, oven, microwave, and dishwasher safe. All of the Catamount glass is assembled and printed in the USA. Borosilicate is one of the purest forms of glass. No heavy metal.