This specimen is a large mass of native copper that is studded with large, rounded globs (up to 15mm) of native silver. The mass, seems to have formed in quartz and most of the specimen has imprints of quartz and perhaps other crystals in it. On one side though, there is an open space where coherent silver(to 7mm) and copper crystals (to 15mm) are present. See the photo. A really nice combination specimen from one of the old classic mines of the Keweenaw!