mineral

Herkimer Diamond

Quartz (Silicon Dioxide - SiO2)

Hardness: 7.5 on Mohs scale (harder than standard quartz at 7.0); Color: Colorless to smoky; Luster: Vitreous/glassy; Structure: Hexagonal crystal system with double terminations; Cleavage: None/Conchoidal fracture.

Hardness: 7
Color: Colorless to smoky
Luster: Vitreous/glassy

Identified June 23, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed roughly 500 million years ago in the Little Falls Dolostone during the Cambrian period. They grew very slowly in vugs (small pockets), allowing for double termination.

Uses & applications

Primarily used for collecting, jewelry, and metaphysical purposes. Their natural beauty makes them popular as un-cut specimens in rings and pendants.

Geological facts

They are not actually diamonds but are double-terminated quartz crystals named for their diamond-like clarity and the fact they were first discovered in Herkimer County, New York.

Field identification & locations

Identify in the field by their distinct double-terminated points and unusual clarity. Found primarily in New York, USA, especially in Herkimer, Fulton, and Montgomery counties.