mineral
Herkimer Diamond
Quartz (Silicon Dioxide, SiO2)
Hardness of 7 on the Mohs scale, colorless or clear (water-clear), vitreous to adamantine luster, trigonal crystal system with distinctive double-termination and 18 total crystal faces, conchoidal fracture, specific gravity of 2.65.
Identified More mineral →
Explore Herkimer Diamond in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, colorless or clear (water-clear), vitreous to adamantine luster, trigonal crystal system with distinctive double-termination and 18 total crystal faces, conchoidal fracture, specific gravity of 2.65.
Formation & geological history
Formed in exposed dolostone rock pockets and cavities through the precipitation of silica-rich solutions during the Cambrian period, approximately 500 million years ago.
Uses & applications
Widely sought after by mineral collectors, used in wire-wrapping and jewelry making, and appreciated for metaphysical properties.
Geological facts
Despite being called 'diamonds', they are actually exceptionally clear and doubly-terminated quartz crystals. They are famous for forming naturally with 18 crystal faces without needing to be cut or polished.
Field identification & locations
Found predominantly in Herkimer County and surrounding areas in upstate New York. Easily identified in the field by their brilliant clarity, double termination, and occurrence within cavities of the Little Falls Dolostone.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Soil with Mineral Detritus and Quartz Fragments
Regolith / Silicate Mineral Aggregate
sedimentary
Limonite / Goethite (Iron Ore Mineral nodule)
FeO(OH)·nH2O / FeO(OH)
mineral
Septarian Pebble
Septarian nodule / Concretion
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral