mineral

Herkimer Diamond

Double-terminated Quartz (Silicon Dioxide, SiO2)

Hardness: 7 on Mohs scale. Color: Clear to smokey. Luster: Vitreous. Crystal structure: Hexagonal (double-terminated). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Clear to smokey
Luster: Vitreous

Identified April 27, 2026More mineral →

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Physical properties

Hardness: 7 on Mohs scale. Color: Clear to smokey. Luster: Vitreous. Crystal structure: Hexagonal (double-terminated). Cleavage: None (conchoidal fracture). Specific gravity: 2.65.

Formation & geological history

Formed in cavities (vugs) within the Little Falls Dolostone during the Cambrian Period (approx. 500 million years ago). The crystals grews very slowly in a saline solution.

Uses & applications

Predominantly used for jewelry, as mineral specimens for collectors, and in alternative healing practices (crystal healing).

Geological facts

They are not actually diamonds; they are named 'diamonds' due to their natural clarity and faceted shape. They are often found with anthraxolite (black carbon) inclusions.

Field identification & locations

Found primarily in Herkimer County, New York. Identify by its double-termination (points at both ends) and natural 18-faceted shape. In the field, look for 'vugs' or pockets in limestone or dolo-limestone.

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