mineral

Herkimer Diamond

Quartz (Silicon Dioxide) - SiO2

Hardness: 7.5 (slightly harder than typical quartz); Color: Transparent to translucent; Luster: Vitreous/glassy; Crystal Structure: Hexagonal with double terminations; Specific Gravity: 2.65

Hardness: 7
Color: Transparent to translucent
Luster: Vitreous/glassy

Identified May 10, 2026More mineral →

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Physical properties

Hardness: 7.5 (slightly harder than typical quartz); Color: Transparent to translucent; Luster: Vitreous/glassy; Crystal Structure: Hexagonal with double terminations; Specific Gravity: 2.65

Formation & geological history

Formed in vugs or cavities of the Little Falls Dolostone during the Cambrian Period. These crystals grew slowly with little attachment to the host rock, allowing for double termination.

Uses & applications

Primarily used in jewelry (earrings, rings, pendants) and as mineral specimens for collectors due to their natural clarity and geometric beauty.

Geological facts

They are not actually diamonds but are called so because of their clarity and natural facets. They are roughly 500 million years old and are a popular gemstone for those who appreciate natural crystals.

Field identification & locations

Identify by looking for double-terminated points and exceptional clarity. Found mostly in Herkimer County, New York, and surrounding areas. Collectors look for flawless, water-clear specimens.