Former: The major component of the glass is silica, which during the Roman period was sand (quartz), which contains some alumina (typically 2.5%) and nearly 8% lime.[1] Alumina contents vary, peaking around 3% in glasses from the western Empire, and remaining notably lower in glasses from the Middle East.[4] Flux: This ingredient was used to lower the melting point of the silica to form glass. Analysis of Roman glass has shown that soda (sodium carbonate) was used exclusively in glass production.[10] During this period, the primary source of soda was natron, a naturally occurring salt found in dry lake beds. The main source of natron during the Roman period was Wadi El Natrun, Egypt, although there may have been a source in Italy.