Quartz is made of

Quartz is an abundant mineral in the Earth’s continental crust. It is made up of a continuous framework of SiO₄ silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO₂. There are many different varieties of quartz, several of which are semiprecious gemstones. Most quartz used in microelectronics is produced synthetically. Large, flawless and un-twinned crystals are produced in an autoclave via the hydrothermal process. The process involves treating crushed natural quartz with hot aqueous solution of a base such as sodium hydroxide.