(April 2015) Corruption in Brazil exists on all levels of society from the top echelons of political power (as seen in the MensalÃ£o Scandal and the Operation Car Wash and the Petrobras scandals) to the smallest municipalities.
Quartz sands, which are high in silica content, are used to make glass. When quartz sands are crushed they produce particles with sharp, angular edges that are sometimes used to make sandpaper for smoothing wood. Some quartz sand is found in the form of sandstone.
Most glass you encounter is silicate glass, which consists mainly of silica or silicon dioxide, SiO 2. This is the type of glass you find in windows and drinking glasses. The crystalline form of this mineral is quartz. When the solid material is non-crystalline, it is a glass. You can make glass by melting silica-based sand. Natural forms of silicate glass also exist. Impurities or additional elements and compounds added to the silicate change the color and other properties of the glass.