Zincite with Franklinite

specimen number:
2262062

location:
Franklin, Sussex Co., New Jersey, USA

description:
Rich masses of brick red zincite in matrix with black franklinite. Good rich example for the species.

The Franklin Mine, located in the Franklin Marble of Sussex County, New Jersey, is part of one of the most mineralogically complex and unique ore bodies in the world. Geologically, the deposit consists of a highly metamorphosed, stratiform zinc-iron-manganese body that was subjected to intense heat and pressure during the Grenville Orogeny over one billion years ago. The locality is the type locality for zincite, which occurs as a primary ore mineral in deep orange to blood-red masses or rare hexagonal crystals, typically found in a granular matrix alongside franklinite and willemite. Historically, mining and quarrying in the Franklin district began in the mid-1700s, though large-scale industrial operations focused on the unique zinc silicate and oxide ores did not peak until the late 19th and early 20th centuries. The New Jersey Zinc Company consolidated the local operations, and the Franklin Mine remained a prolific producer until its final closure in 1954 due to the exhaustion of the ore body. As of 2026, the site is recognized globally as a mineralogical "wonder of the world," celebrated for its incredible diversity of fluorescent minerals and its vital role in the history of American mining.

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