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Corundum : Al2O3 | |
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Corundum Hill, Unionville, Newlin Township, Chester Co., Pennsylvania, USA Hexagonal Crystal of Corundum with blackish surface coloration and vitreous luster. Exposure at the base of the crystal shows actual coloration of deep Reddish-brown and exhibits distinct asterism. Specimen is from Chester Co., PA., Crystals of this quality occur only at Corundum Hill, at Point Prospect, Near Unionville, Newlin Township, ... |
| © M.Heintzelman | Photo ID: 15218 View Count: 454 |
Margarite : CaAl2[(OH)2|Al2Si2O10] | |
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Corundum Hill, Unionville, Newlin Township, Chester Co., Pennsylvania, USA Aggregate of platy camel colored crystals of Margarite. Specimen from Corundum Hill, Unionville, Chester Co, Pennsylvania. Margarite commonly occurs in association with, as coatings on, or replacements of Corundum at this site. Specimen size: 6.5 x 5cm. From the PA Annex of my personal collection, acquired in 2005. |
| © M.Heintzelman | Photo ID: 52312 View Count: 360 |
Margarite : CaAl2[(OH)2|Al2Si2O10] | |
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Corundum Hill, Unionville, Newlin Township, Chester Co., Pennsylvania, USA Aggregate of platy margarite, found on a specimen of diaspore - an older specimen, with W. W. Jefferis and Michigan College of Mines prior labels. S405-13 #1253# 4 cm specimen. |
| © 2007, JGW | Photo ID: 142538 View Count: 131 |
Muscovite (Var: Damourite) : KAl2[(OH)2|AlSi3O10] | |
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Corundum Hill, Unionville, Newlin Township, Chester Co., Pennsylvania, USA 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 ... |
| © M.Heintzelman | Photo ID: 32233 View Count: 685 |
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