Herkimer Diamond

Local name for clear, doubly-terminated, usually quite clear and highly lustrous, quartz crystals from cavities in dolostones in Herkimer Co., New York, and surrounding areas, USA. They are frequently doubly terminated with prism faces about as prominent as the pyramidal terminations. They were originally (1790) named "Little Falls Diamond(s)". There are similar terms for quartz crystals from numerous other worldwide locales, all formed under low-temperature hydrothermal conditions in sedimentary rocks and often containing hydrocarbon inclusions.

Herkimer diamonds have been popular with collectors for more than 100 years and various localities for them in Herkimer Co. are still producing many specimens each year even though it requires a lot of hard manual labor to find good specimens.

A number of other localities produce Herkimer-like quartz crystals, but few of them can produce crystals that match the perfection, luster and transparency of the best Herkimer diamonds. People selling Herkimer-like quartz crystals from other localities often try and trade on the name by calling their quartz Herkimer quartz or Herkimer diamonds. Of course this irritates the collectors of real Herkimer quartz and they will assert that Herkimer diamonds only come from the area around Herkimer Co., New York. Sort of like certain French people insisting that the only Champagne comes only from a particular region of France.

Click here for the Herkimer County, New York, USA locality page Herkimer quartz crystals: https://www.mindat.org/loc-4010.html[Rock Currier 2012]