Crabtree Mine (Big Crabtree Emerald Mine), Spruce Pine, Spruce Pine District, Mitchell Co., North Carolina, USA
|Latitude & Longitude (WGS84):||35° 52' 29'' North , 82° 7' 12'' West|
|Latitude & Longitude (decimal):||35.87472,-82.12000|
|Köppen climate type:||Cfb : Temperate oceanic climate|
An emerald mine located about 6.2 kilometers (4 miles) SW of Spruce Pine.
The Crabtree pegmatite is a beryl (emerald, green beryl, aquamarine and yellow beryl) and tourmaline-bearing granitic pegmatite. Emerald and green beryl occurs in the biotite and chlorite selvage and the pegmatite margin. Aquamarine and yellow beryl occurs in the pegmatite core. Green and purple fluorite, white mica, almandine-spessartine garnet and xenotime are accessory minerals. It has been sporadically mined for gem-quality beryl from 1894 to the late 1970’s and has produced a number of good quality emeralds, one of which was 70 carats. The pegmatite intrudes at the boundary between garnet-titanite-zoisite bearing hornblende-plagioclase gneiss (blastomylonite) and plagioclase-quartz-biotite-white mica porphyroclastic gneiss. (Source: Tappen, et al, 2006).
Mining operations at the Crabtree Emerald Mine began in July of 1894 by J.L. Rorison and D.A. Bowman. The emeralds at the mine occur in a pegmatite vein approximately five feet wide with well-defined walls. Mineral rights to the Crabtree were acquired by the American Gem and Pearl Company of New York in 1905. The company operated the mine several years and marketed the rock as "emerald matrix". The material was cut en cabochon. Although most of the gem material was sold as "emerald matrix", early mining operations did produce fine clear gems suitable for faceting. The deeper the shaft was sunk, the larger the emeralds that were found, many up to one inch in diameter and one inch long. The American Gem and Pearl Co. discontinued operations in 1908. The mineral rights to the property were then purchased by Edward Fortner and J.P. Grindstaff. In recent years the Crabtree was mined commercially from 1968 to 1974 during which time, fee collecting was allowed on the dumps. In the 1980's the mine was closed for some time. The mineral rights were purchased in 1984 by the partnership of Ted Ledford, Bert Roper and Dal Duppenthaler, the new owners actively mined the site. In 1985 the mine was called "Gem Haven" and public collecting was allowed on the dumps at the mine. As of 1994 the mine was closed and has set idle for many years with the occasional collector visiting the site. In 2003, Bert Roper and Dal Duppenthaler acquired sole ownership of the mine. As of 2009, in an agreement with the Mountain Area Gem and Mineral Association, the mine has been reopened to the public under the management of the M.A.G.M.A. Club. (Source: Alex Glover, M.A.G.M.A., 2009, pers. comm.to Harjo Neutkens).
20 valid minerals. 1 (TL) - type locality of valid minerals.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
541 - 1000 Ma
|Alligator Back Formation; Amphibolite|
Age: Neoproterozoic (541 - 1000 Ma)
Stratigraphic Name: Alligator Back Formation
Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052.