Franklin Marble Page 1
The Franklin Marble is exposed in a continuous band from Sterling
Hill in Ogdensburg, Sussex County, NJ to Mount Adam and Mount
Eve in Warwick, Orange County, NY. The marble is host to the
world famous zinc ore bodies at Franklin and Sterling Hill where
over 350 different mineral species occur. Other 'classic' mineral
localities, such as the spinel localities in Orange County, NY, are
also found in the Franklin Marble. It is part of a metamorphosed
sedimentary sequence of Grenville age, about 900 million to one
billion years old, located on the northwestern edge of the Reading
Prong geologic province of New York, New Jersey and Pennsyl-
vania. The marble itself is a highly metamorphosed limestone
(sillimanite grade) and is a well known producer of collectible
specimens of metamorphic minerals including the largest spinels
from North America. The specimens pictured here come from a
variety of localities in the marble except the zinc mines of Frank-
lin and Sterling Hill which merit separate attention due to the large
variety and unusual nature of the minerals found in them.
M1146
CLINTONITE, CHONDRODITE,
DIOPSIDE
Amity, Orange County, NY, USA
Bronze colored clintonite, a brittle mica, in
brecciated orange chondrodite, violet titanium-
rich diopside
Specimen size - approx. 10.5 cm. X 8.0 cm. X 2.5 cm.
M1884
ARSENOPYRITE
Warwick, Orange County, NY, USA
Silver arsenopyrite crystals in a mixed mica,
pyroxene matrix.
Specimen size - approx. 6.0 cm. X 3.8 cm. X 2.8 cm.
M1738
SPINEL
Amity, Orange County, NY, USA
Cluster of black spinel octahedra with minor
phlogopite and pyroxene.
Specimen size - approx. 15.0 cm. X 10.0 cm. X 7.0 cm.
M1585
ZIRCON
Amity, Orange County, NY, USA
Brown zircon crystals with graphite in
diopside/scapolite rock at marble contact.
Specimen size - approx. 12.0 cm. X 8.5 cm. X 5.5 cm.