Herkimer Diamond

Physical Properties

Hardness: 7 (Mohs scale); Color: Colorless/transparent with potential inclusions; Luster: Vitreous/glassy; Crystal structure: Hexagonal with double termination; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65.

Formation & Geological History

Formed in vugs (cavities) within the Little Falls Dolostone during the Cambrian period. Silica-rich waters seeped into limestone pockets and slowly crystallized under high pressure and low heat.

Uses & Applications

Primarily used for mineral collecting, jewelry (often in its raw state), and believed by some to have metaphysical properties.

Geological Facts

They are not actually diamonds but are called so because of their clarity and natural facets. They are exceptionally clear and naturally double-terminated, meaning they have points on both ends without being cut.

Field Identification & Locations

Identify in the field by looking for vugs in dolostone matrix. Most famously found in Herkimer County, New York. In the field, look for sparkling crystals inside rocky pockets of host dolostone.

Identified on: 5/19/2026

Mode: Standard