In ancient times, the first glassmakers’ kilns were built of earth and fuelled by wood. This type of pot furnace is still used today in glass factories, heated with gas or oil. The circular or rectangular furnace has up to sixteen pots with a capacity of 1,000 litres of molten glass each. At Lalique, the hot workshop is equipped with a twelve-pot furnace and an electric basin furnace, which allows a continuous casting of several tons of crystal per day. The traditional fireclay pot furnace is used for coloured crystal, while the basin furnace is used for clear crystal.