Gahnite
specimen number:
2102319
location:
1120 Crosscut, 700', Sterling Hill Mine, Ogdensburg, New Jersey, USA
description: The Sterling Hill Mine, located in Ogdensburg, Sussex County, New Jersey, is a world-renowned mineralogical site situated within the Reading Prong of the Highlands. Geologically, the deposit consists of a massive, stratiform zinc-manganese-iron ore body hosted in the Mesoproterozoic Franklin Marble, which underwent high-grade regional metamorphism during the Grenville Orogeny. The mine is famous for its unique mineralogy, including gahnite, a zinc aluminum oxide that typically occurs as sharp, dark green to nearly black octahedral crystals embedded within the marble or associated with franklinite and willemite. Historically, the site saw small-scale mining and quarrying as early as the 1730s, but large-scale industrial operations began in the mid-19th century under various companies that eventually merged into the New Jersey Zinc Company. The Sterling Hill Mine operated almost continuously from the 1870s until its final closure in 1986 due to economic conditions. Following its cessation of production, the site was preserved and reopened as the Sterling Hill Mining Museum in 1990, allowing for continued educational access to one of the most complex mineral deposits on Earth.
Very fine example for the species with lustrous octahedral crystals to 1.0 cm in size across the front of matrix. This is in good condition.
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