The first mass produced pieces of artwork were the ancient Egyptians shabtis which were essentially miniature mummies that the ancient Egyptians believed had magical powers and were therefore buried with the dead. Shabtis were comprised of Egyptian faience which is a type of glass ceramic material made from sand. Egyptian faience is referred to as such in order to distinguish it from faience, which is a tin glazed pottery associated with Faenza, Italy. The idea of Egyptian faience was to replicate semiprecious stones like turquoise lapis lazuli from Afghanistan, which at the time was more expensive than gold. The recipe for Egyptian faience is 90% crushed silica, crushed fine natron salt to act as a flux, crushed limestone, and then the coloring with blue being the most popular, a color achieved through the use of pure copper oxide. Water was introduced to turn this composition from a granular mix into a dough like substance. Natron salt which is a type of baking soda, is the key ingredient to this recipe as it rises to the surface when baked and lowers the overall temperature at which sand melts and becomes glass. The statues are left to stand for 24 or more hours as this helps the salt grow on the surface through a chemical reaction process as oxygen within the ambient environment mixes with the ingredients inside the Egyptian faience