There is evidence of glass casting from 1500 BC from Egypt and Mesopotamia, where fireproof clay vessels were used to produce small amulets, objects and flaçons.
Using extremely dry firewood and a bellows made it possible to achieve temperatures of up to 1300°C. The glass was formed around a grain of sand, hence the alternative name for the process: sand casting. Due to naturally present metallic salts in the sand, the glass was opaque. This technique was common for a millennium.
