A group of
emery mines located in the town of Chester, Massachusetts. The early history of the deposit was described by Lewis (1896): "In 1864, the occurrence of emery at Chester, Massachusetts was predicted by Dr. C. T. Jackson from his discovery of
margarite there -- a mineral which Dr. J. L. Smith had just found characteristic of the emery deposits of Asia Minor. On September 6th of the same year, Dr. H. S. Lucas discovered the emery in what had before been considered only deposits of magnetic iron ore. Two years later, distinct crystals of
corundum were found in the same deposits. The discovery of emery soon led to the establishment of active mining, the first of its kind in America."
This is the type locality for the mineral
amesite, named for one of the original mine owners, James T. Ames (1810-1883) of Chicopee, Massachusetts. He also owned Ames Manufacturing Company, a Chicopee company which had government contracts for making swords and cannons during the Civil War. Ames was interested in mineralogy and had a collection of rare and unusual minerals.
The type of deposit is debatable. Old references suggest it is a stratabound deposit, enriched by regional metamorphism. But in recent years it has become recognized that the deposits are located along a major thrust fault - the primary evidence being ultramafic tectonic slivers which occur all along the stratigraphic horizon of the deposits. The deposits themselves may be thrust fault slivers of aluminous rock, or they may be hydrothermal deposits - or a combination of both. The old Chester emery mines are divided into two groups: North of Rte 20 - Macia Mine, Sackett Mine, and Snow Mine. South of Rte 20 - Old Mine, Melvin Mine, and Wright Mine. The most frequented site is the Old Mine, located closest to Rte. 20. This mine, the Melvin, and the Sackett are actually mining complexes involving combinations of open cut and underground workings. The Macia and Snow mines are mostly underground workings, and the Wright mine is largely an open cut. The Old Mine is the most extensive, having been opened first and operated the longest, involving perhaps half a mile of horizontal levels interconnected by stopes and internal shafts. The open pit at this mine is actually a collapsed section of the second level.
Note: Persistent reports of "
schorl" from these sites are attributed to mis-identifications of ferrohornblende or dravite crystals. Schorl has not been proven to exist here. Reports of
azurite are mis-identifications of
carbonate-cyanotrichite. Azurite has not been found here. "
Corundophyllite" was discredited as a species. The following mineral list includes all species reported for the group of mines.
References:Jackson, C. T. (1864): Discovery of Emery in Chester, Hampden County, Massachusetts (
Proceedings of the Boston Society of Natural History 10:84).
Shepard, C. U. (1865): A Description of the Emery Mine of Chester, Hampden County, Massachusetts (pamphlet, 16 pp., London, 1865)
Smith, J. L. (1866): On the Emery Mine of Chester, Hampden County, Massachusetts (
American Journal of Science 17:83-93)
Emerson. B. K. (1895): A Mineralogical Lexicon of Franklin, Hampshire, and Hampden Counties, Massachusetts.
Lewis, Joseph V. (1896): "Historical Sketch of Corundum Mining in America" in Corundum and the Basic Magnesian Rocks of Western North Carolina (North Carolina Geological Survey Bulletin 11), p.88.
Pratt, J. A. (1906):
Corundum and Its Occurrence and Distribution in the United States (USGS Bulletin 269)
Palache, Charles and Wood, H. O. (1909): Crystallographic Notes on Minerals from Chester, Mass. (Contributions from the Harvard Mineralogical Museum, No. 14).
Shannon, Earl V. (1919): Famous mineral localities: The Chester emery mine (
American Mineralogist 4:69-73)
Shannon, Earl V. (1920): Analysis and optical properties of
amesite and corundophilite from Chester, Massachusetts...(U.S. Nat. Mus. Proc. 58:371-379).
Apfel, Earl T. (1945): Emery deposits near Chester, Massachusetts (USGS Open-File Report 45-58).
Lincks, G. Fred (1978): The Chester
Emery Mines (
Mineralogical Record 9:235-242)
Francis, C. A. and D. E. Lange (1988): Four Occurrences of Dravite in Western New England (
Rocks and Minerals 63:455).
Plante, A. (1992): Western Massachusetts Mineral Localities (Valley Geology, Greenfield, Mass)
