mineral

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, colorless or clear with a vitreous to adamantine luster, trigonal crystal system with double-termination, conchoidal fracture, and no true cleavage. Specific gravity is approximately 2.65.

Identified July 29, 2026More mineral →

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Physical properties

Formation & geological history

Formed in exposed dolostone cavities (specifically the Little Falls Dolostone) during the Cambrian period, approximately 500 million years ago, via silica-rich hydrothermal fluids.

Uses & applications

Used primarily in lapidary work, wire-wrapped jewelry, spiritual healing practices, and as collector specimens.

Geological facts

Despite being called 'diamonds', they are actually exceptionally clear, double-terminated quartz crystals. They are famous for naturally forming with 18 faces (six on each point and six around the center).

Field identification & locations

Found mainly in Herkimer County, New York, and surrounding areas. To identify them, look for naturally double-terminated transparent quartz crystals often embedded in grey dolostone rock matrix.