Exceptional specimen in Smithsonian Istitution 12.7 x 15.3 cm, Canfield collection [see Bancroft, Peter (1973) The World's Finest Minerals and Crystals].
Quality for species:
Excellent - world class for species or very significant. (!!)
Significance:
Classic locality for this mineral (see references.)
Sterling Mine, Antwerp, Jefferson County, New York, USA