This is the cotype specimen of gerstmannite, photographed to show the layered structure of the vein and the nature of the matrix rock. The gerstmannite is the faintly pink mineral in the top left quadrant of the specimen. To its right is white calcite showing reflections from cleavage planes, and beneath both is massive brown sphalerite. The matrix rock is typical granular willemite-franklinite-calcite ore. This is specimen FMM-592 in the collection of the Franklin Mineral Museum and used to be in the collection of Ewald Gerstmann of Franklin, NJ.
Identifier: GST3a Locality: 1120 stope above 1100 level, Sterling mine, Ogdensburg Specimen size: 9.5 x 5.5 x 3.5 cm Photo credit: Charles Mazel (Nightsea, Lexington, MA)
