The Spruce Pine district in Western North Carolina is the only producer of high-purity quartz in the world, amounting to 90% of all mined and processed quartz for use in the electronics industries. The three principal markets for this high-purity quartz include electronics for semiconductors, solar markets for the production photovoltaic cells, and applications in the lamp tubing market.
As an example, Unimin Corporation, with its IOTA-branded quartz from Spruce Pine, is a worldwide supplier to the glass, ceramic, and lighting industries, to oil and natural gas service companies, and to paint, plastic, rubber, and composite manufacturers.
Additionally, quartzites of the Chilhowee Group in northern McDowell County have potential to be a source of high-silica material. Mineral dressing data show the silica concentrate is suitable for plate glass and container glass and, upon further grinding, as a source of fine-ground silica. Quality quartz is also produced in the Kings Mountain district.