Intergrown plates of light purple diaspore crystals on a quite heavy (corundum-bearing?) matrix rock. Rare and classic material, these are some of the most well known diaspore specimens outside of Turkey.

From a very old american locality that was so important it was mined up: 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." (cit. mindat)

Comes with two old labels, one from Möhler, Graz, Austria and one from George English, dated around 1900.