It was actually a mistranslation using a homonym. The original word was "vair" meaning the fur of the Siberian grey squirrel or one of the furs of the crown; an expensive fur at the time. The word "verre" is the French word for glass. Cinderella was written by Charles Perreualt, a French civil servant, in before 1720. He also wrote, Sleeping Beauty, Little Red Riding Hood, Puss in boots, Beauty and the Beast,