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Roeblingite, October 2012 Mineral of the Month

Roeblingite, October 2012 MOTM

Mineral Name: Roeblingite
Specimen Number: 001
Record ID: 5949
Locality Nickname: Franklin, New Jersey
State: New Jersey
County: Sussex
Town: Franklin
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This nodule may look like a simple porcelain mass, but it is in fact one of the better specimens of the extremely rare mineral roeblingite, Pb2Ca6(SO4)2(OH)2(H2O)4[Mn(Si3O9)2].  This mineral is known to occur from only two localities, the Parker Shaft of the Franklin Mine, near the town of Franklin, New Jersey; and from a similar deposit in Sweden. The finds were made in the late 19th century from the shaft, with fragments later found in the dumps. Another smaller find was made in the 1950s, with no more found since then. This is one example of the incredible diversity of rare minerals from the small mining district in Sussex County, operated by the New Jersey Zinc Company (owned by the Palmer family) in the first half of the 20th century. Colonel Washington A. Roebling served in the Civil War, and later worked as a civil engineer based in Trenton best known for designing the Brooklyn Bridge.  Roebling was an avid mineral collector, having assembled one of the world’s finest collections, which was donated to the Smithsonian by his son after his death.