“…However, most of the mines ascribed with high chemical purity, are rocky quartz deposits, but there are a number of quartz sand deposits as well. Most quartz sand deposits explored in the country are located in south and southeastern Brazil (Ruiz et al, 2013;Cruz, 2011) and are widely used by float glass manufacturers. Those resources, however, are not as pure as the rocky quartz deposits, what make them unattractive for silica glass manufacturers.…”