|Location is approximate, estimate based on other nearby localities.|
|Latitude & Longitude (WGS84):||39° North , 75° West (est.)|
|Margin of Error:||~6km|
|Köppen climate type:||Cfa : Humid subtropical climate|
Old Garnet mines, 1 mile southwest of Chelsea (abandoned). Host rock is Baltimore Gneiss. Garnet occurs massive and in gabbro at the contact point of serpentinite and gabbro, at approximately the lay of Green Creek bed.
Knowledge of these deposits were recorded as early as 1843, however interest in exploiting them did not come until the mid 1870's. First was Charles Williams, who owned the farm on which the deposits were located. His interest lay merely on the ornamental uses of the larger crystals, but quality crystals of size proved few and far between. The deposits soon attracted the attention of "Mineral John" Smedley, a then famous local prospector/mineralogist. Having no luck garnering the interest of local entrepreneurs, Mr. Smedley eventually peaked the interest of the Herman Behr & Co. of 79 Beekman Street, New York, which set up operations at the site in 1879. The garnets were recovered for use in abrasive papers, grinding wheels and marble polish. These deposits proved to be of a good quality, and plentiful enough to continue operation of the mines until as late as 1912.
The open pit workings of the original Behr Mine are now largely gone. The Conchester Highway (Route 322) was built through the middle of the pit, and though the back wall still exists, no mineralized zones have been observed. The area currently collected is actually the site of the American Glue Company Mine. Only Garnet Mine Road separated this site from the Behr workings, and was operated briefly by Behr after American Glue Co. pulled out. (reference/observations: J. Roger Mitchell, Delaware County Institute of/for Science)
Regions containing this locality
|North America Plate||Tectonic Plate|
Select Mineral List TypeStandard Detailed Strunz Dana Chemical Elements
Commodity ListThis is a list of exploitable or exploited mineral commodities recorded at this locality.
6 valid minerals.
Detailed Mineral List:
Formula: (Al2O3)(SiO2)1.3-2 · 2.5-3H2O
List of minerals arranged by Strunz 10th Edition classification
|Group 4 - Oxides and Hydroxides|
|Group 9 - Silicates|
|ⓘ||Allophane||9.ED.20||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
|Unclassified Minerals, Rocks, etc.|
List of minerals arranged by Dana 8th Edition classification
|Group 51 - NESOSILICATES Insular SiO4 Groups Only|
|Insular SiO4 Groups Only with cations in  and > coordination|
|Group 52 - NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O|
|Insular SiO4 Groups and O, OH, F, and H2O with cations in  and > coordination|
|Group 71 - PHYLLOSILICATES Sheets of Six-Membered Rings|
|Sheets of 6-membered rings with 1:1 layers|
|ⓘ||Allophane||188.8.131.52||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
|Sheets of 6-membered rings with 2:1 layers|
|Group 75 - TECTOSILICATES Si Tetrahedral Frameworks|
|Si Tetrahedral Frameworks - SiO2 with  coordinated Si|
|Unclassified Minerals, Mixtures, etc.|
List of minerals for each chemical element
|H||ⓘ Allophane||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
|O||ⓘ Allophane||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
|Al||ⓘ Allophane||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
|Si||ⓘ Allophane||(Al2O3)(SiO2)1.3-2 · 2.5-3H2O|
Sort byYear (asc) Year (desc) Author (A-Z) Author (Z-A)
Gordon, S. (1922), Minerals of Pennsylvania: 185.
Geyer, A.R., Smith, R.C. & Barnes, J.H. (1976) Mineral Collecting in Pennsylvania.
Roger, Mitchell, J. (2001), The Garnet Mines of Chelsea, Pennsylvania, an Historical Perspective, Matrix: 9: 35-46.
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