An uncommonly fine (for the locality) azurite specimen from Franklin. The azurite is present as a druse of tiny, lustrous crystals associated with dull green malachite on limonitic matrix. The specimen is probably from the zone of oxidation high along the northern part of the west limb of ore at Franklin, where, during Late Proterozoic time, a gossan cap had developed on ore exposed at and near the surface. The gossan was later buried beneath the Hardyston Quartzite, the earliest of the Paleozoic sedimentary rocks to be deposited in the region. National Museum of Natural History specimen R2691.
Identifier: AZR6a Locality: Franklin mine, Franklin Specimen size: 8 cm across Photo credit: Pete J. Dunn