mineral

Herkimer Diamond

Quartz (SiO2)

Hardness: 7 (Mohs scale); Color: Colorless/transparent; Luster: Vitreous (glassy); Crystal structure: Hexagonal (doubly terminated); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

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

Identified March 15, 2026More mineral →

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Physical properties

Hardness: 7 (Mohs scale); Color: Colorless/transparent; Luster: Vitreous (glassy); Crystal structure: Hexagonal (doubly terminated); Cleavage: None/Conchoidal fracture; Specific gravity: 2.65

Formation & geological history

Formed in Cambrian-age dolostone (Little Falls Formation) approximately 500 million years ago. These crystals grew slowly in vugs (cavities) within the rock, allowing them to form points on both ends without being attached to a matrix.

Uses & applications

Used primarily for jewelry (rings and pendants), metaphysical collection, and as a popular specimen for mineral enthusiasts and geological tourism.

Geological facts

Despite the name, they are quartz, not diamonds. They are called 'diamonds' due to their natural clarity and faceted-like appearance. They were first discovered in large quantities in Herkimer County, New York.

Field identification & locations

Identified by its double-termination (pointed at both ends) and water-clear transparency. Primarily found in vugs within the dolostone of the Mohawk River Valley in New York, USA. Collectors should look for the dark carbonaceous material (anthraxolite) often associated with the pockets.