(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.
Common silicate glass, the material used in window panes and iced tea glasses, is a mixture of sand, sodium-carbonate and limestone. Add boric oxide to it and, you guessed it, borosilicate glass is created. A +5% infusion of boron provides a less dense product with a higher melting point, making it useful for lots more than kitchen cooking.