mineral

Herkimer Diamond

Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (doubly terminated); Cleavage: None; Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Colorless/Transparent
Luster: Vitreous (glassy)

Identified March 25, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale; Color: Colorless/Transparent; Luster: Vitreous (glassy); Crystal Structure: Hexagonal (doubly terminated); Cleavage: None; Specific Gravity: 2.65

Formation & geological history

Formed in vugs (cavities) within the Little Falls Dolostone (sedimentary rock) during the Cambrian Period, approximately 500 million years ago. These crystals grew slowly from hydrothermal solutions.

Uses & applications

Predominantly used as a collector mineral and in the creation of unique wire-wrapped or naturally-set jewelry. Also used by practitioners of crystal healing.

Geological facts

They are not actually diamonds, but are called 'diamonds' due to their natural clarity and faceted shape. Unlike most quartz, they are naturally doubly terminated, meaning they point at both ends.

Field identification & locations

Identify by looking for the 18 natural facets and double terminations. They are almost exclusively found in Herkimer County, New York, and surrounding areas. Collectors look for high clarity and 'smoky' inclusions or anthraxolite (black carbon) spots.