Herkimer County
Curated by Maggie Liu · Updated:
Herkimer County, New York, gives its name to “Herkimer diamonds” — doubly-terminated, water-clear quartz crystals of exceptional natural sharpness.
About Herkimer Countyextended article
Herkimer County, New York, is the source of the famous 'Herkimer diamonds' — exceptionally clear, doubly-terminated quartz crystals that grew free inside cavities in ancient dolostone.
Crystals grown in a rock cavity
Despite the name, Herkimer diamonds are quartz, not diamond. They formed in gas pockets within a Cambrian dolostone, where they grew unattached and developed natural points at both ends — a habit that gives them their gem-like sparkle.
What collectors look for
The prize is water-clear, doubly-terminated quartz with bright faces, sometimes enclosing bubbles, water, or black anthraxolite. Clean 'floater' crystals and aesthetic clusters in the host rock are the most sought-after.
Frequently asked questions
Where is Herkimer County?
Herkimer County is a mineral locality in New York, USA. It lies at approximately 43.0300°N, 74.9700°W. Elevation is about 250 m.
What minerals are found at Herkimer County?
Signature minerals from Herkimer County include Quartz. The locality lies in New York, USA, and each mineral links to a full reference entry with formula, crystal system, and collector notes.
What is Herkimer County known for?
Herkimer County, New York, gives its name to “Herkimer diamonds” — doubly-terminated, water-clear quartz crystals of exceptional natural sharpness.
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