Herkimer diamonds are actually not diamonds at all, but stunning and unique formations of quartz. Famous to Upstate New York, these crystals display double-terminated growth and are popular will all kinds of collectors.

Druzy crystals like these formed in open cavities of dolomite rock called vugs. When mineral-rich water seeps into these openings, it can leave behind the materials necessary to grow thousands of crystals over millions of years.

Similar formations have also been found over the world, including Italy, Iran, Austria, and South Africa. However, true Herkimers only come from New York, where professional miners and amateur rockhounds are always on the hunt for a new find.

These crystals come from New York's Little Falls Formation, which dates back to the Cambrian over 486,000,000 years ago. They are prized pieces of any geologist's collection and are incredible to hold in your hand.

Each Herkimer diamond druzy cluster has been photographed and listed individually by size, so you can select the perfect specimen for your collection. Every item is packed in a sturdy shipping carton and comes with a certificate of authenticity.

You can explore the entire selection of Herkimer diamonds in the collection below!

Within the dolomite deposits of Upstate New York, a geologic wonder lies waiting to be found. These stunning quartz crystals are known as Herkimer diamonds, so named for their source in Herkimer County and their magnificent clarity.

Quartz is composed of silicon dioxide pairs linked in tetrahedra, and makes up the base of many beautiful minerals like amethyst, citrine, and rose quartz. Herkimer diamonds are their own wonderful members of the quartz family with crystals that form double-terminated growths, meaning they come to pointed facets on both ends. The Herkimer source of the crystals is the Little Falls Formation, a Cambrian Period dolostone deposit. Human interaction with Herkimer diamonds dates to at least the sixteenth century when local Native Americans traded the crystals and used them in religious ceremonies.

Herkimer diamonds can be identified both by their striking hexagonal-bipyramidal crystals and their presence near petroleum and coal deposits. Because of their proximity, it’s speculated that Herkimer diamonds may hold hydrocarbon inclusions—small pockets of trapped fluids and gases.

Quartz crystals are abundant throughout the dolostone formation, but true Herkimer diamonds can only be found at one sedimentary layer, dubbed “the table.” Here, after digging through at least four feet of rock, one finds large pockets of druzy crystals that measure 1-4 feet in diameter. These pockets, called vugs, are often filled with mud and quite dirty, but they can yield up to 1,000 individual crystals. Mining these pockets of crystals is no easy task, but the end result speaks for itself: beautiful crystal formations, well deserving of their “diamond” status.