FROM GEMS TO ABRASIVES: THE FASCINATING HISTORY OF MINING CORUNDUM IN NORTH CAROLINA

The mining of corundum in North Carolina supplied a large amount of the world’s industrial corundum, with the exception of emery, from 1871 to 1900. Corundum (Al₂O₃) was ideal for the manufacture of a variety of abrasives as well as emery boards, toothpaste and aluminum alloys. There are three types of corundum: industrial, gem variety and emery. Industrial corundum is crystalline and colors range from colorless to black. Emery is not crystalline and has a similar range of color. Gem varieties are transparent to translucent and have range of colors. The red (ruby) and blue (sapphire) were sought after for jewelry and ornamental decoration.

Small-scale mining in North Carolina began in 1871 by Hiram Crisp and Dr. C.D. Smith, at Corundum Hill in Macon County. This location is in the “Corundum Belt” that extends from the Georgia line through nine western North Carolina counties. In these counties, the corundum is associated with magnesium-rich rocks (peridotite), as well as variety of metamorphic rocks (gneiss and schist). Most of North Carolina large-scale mining and production was centered in Clay and Macon counties.

The first systematic mining of industrial corundum in the United States began when the Corundum Hill mine was sold to Col. C.W. Jenks and E.B. Ward. Their original purpose was to mine gem quality corundum. However, due to the low number of gem quality stones found, the company was forced to make the mining of industrial corundum its primary objective. The Corundum Hill Mine was the most prolific corundum source for North Carolina. After 1895, the American Prospecting and Mining Company of New York (Cowee Valley; Clay County) started large-scale placer operations (“fluvial mines”) while the Hampdon Corundum Wheel Co. (Corundum Hill; 1914 to 1919) started larger scale surface mines (open pit) in the region. The overall reported amount of corundum mined from North Carolina was as much as 7,000 tons for this region.

Although the mining of corundum was very profitable from the 1870’s to the early 1900s, there is little mining interest in North Carolina today. Foreign mining, as well as synthetic corundum made by flame fusion and flux growth processes, is much cheaper than mining from the Corundum Belt. However, gem collectors and mineralogist still come to western North Carolina mines in hopes of finding sapphires, rubies and other gem varieties of corundum.