Specimen of Damourite, a compact variety of Muscovite with a notable greasy feel, often forming as a pseudomorph of corundum at this locality. Old 19th Century label list locality as Balls Corundum Mine, definitively dating this specimen to the latter half of the 1870's, when George Ball of Wilmington Delaware, along with Spencer Chandler, owned and operated the diggings at Corundum Hill. Also ex. Michigan College of Mines label, Acquired from the Jay Lininger collection. Specimen size: 7 x 3cm. From the PA Annex of my personal collection, acquired in 2005.
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