History of glass
The history of glass-making dates back to at least 3600 years ago in Mesopotamia. However, they may have been producing second-rate copies of glass objects from Egypt, where this complex craft originated. Other archaeological evidence suggests that the first true glass was made in coastal north Syria, Mesopotamia or Egypt. The earliest known glass objects, of the mid second millennium BC, were beads, perhaps initially created as the accidental by-products of metal-working (slags) or during the production of faience, a pre-glass vitreous material made by a process similar to glazing. Glass products remained a luxury until the disasters that overtook the late Bronze Age civilizations seemingly brought glass-making to a halt.
Ancient glass trade
Glass shows up in Northern India at the end of the 2nd millennium BC becoming more common throughout South East Asia during the following millennium. Glass beads in particular become extremely popular and together with bangles form the largest group of glass finds. From its Indian origins, glass beads spread to an area from Africa to Japan, sailing with the monsoon winds and leading to their christening as 'Trade wind beads'. The most common compositional type, representing 40% of the glass finds for the region, is known as mineral soda-alumina glass and is found from the 4th century BC to the 16th century AD. As the name indicates this it is typically characterized by a high alumina content and was made by the probably melting of "reh" with local, alumina rich, sands. Through LA-ICP-MS analysis, however, Carter found that Cambodia had a large amount of glass beads made of potash glass and predominantly high alumina soda glass. Potash glass is a glass that uses potash or K2O as a flux in order to decrease the melting point of the glass and is the most common type of glass found in SE Asia.