Spruce Pine district

The quartz in this district ends up inside semiconductors, and the sand ends up in the bunkers at Augusta National.

Spruce Pine is the largest town in Mitchell County, North Carolina, with 2,194 people at the 2020 census, and the mining district named after it is one of the only places in the world where high-purity quartz can be found. That quartz is required for a range of products that matter a great deal, semiconductors among them. The town is also the exclusive supplier of sand to Augusta National Golf Club.

The town exists because of a railway. Spruce Pine was founded in 1907 when the Clinchfield Railroad came up the North Toe River from Erwin, Tennessee, and grew around a tavern run by Isaac English on the old road from Cranberry down to Marion. The Old English Inn still stands where it always did near the centre of town. Rail plus a fast-expanding mining industry made this the largest town in the Toe River Valley and the hub of the area, home to The Feldspar Company and to Spruce Pine Mica.

North Carolina's geological survey sets out what is actually mined. Feldspar was first worked in the state here in 1911, and this is the main feldspar-producing district in North America. The original mining took pegmatite bodies; current mining works alaskite, a very coarse-grained pale rock of feldspar, quartz and muscovite, averaging about 40 per cent plagioclase, 25 per cent quartz, 20 per cent microcline and 15 per cent muscovite. It is processed by three-stage acid circuit flotation, and mica and silica come off as by-products.

Mica has its own long history here. Large-scale mica mining began in western North Carolina around 1868 and the area became the most important producer in the United States. Sheet mica was the main product for many years until other materials displaced most of its uses, and the state has not produced significant sheet mica since about 1962. Scrap mica is still produced in quantity.

Fortunes here have dwindled with the decline of rail freight and the automation of mining.