Herkimer diamonds are doubly terminated quartz crystals, not true diamonds, named for Herkimer County, New York, where they form freely inside pockets within Cambrian-to-Ordovician dolostone. Because they typically grow without ever being attached to a cavity wall, they develop sharp, glassy facets and a natural point on both ends straight out of the ground, with no cutting or polishing required to show their clarity.
At Mohs hardness 7, quartz is durable enough for regular handling; a soft, dry cloth keeps it clean. This is a smaller, more affordable example of the type — a genuine way to start a Herkimer collection or add a locality piece from the region that gave Herkimer diamonds their name, without the price tag of a larger cluster or matrix specimen.
Inside the Herkimer Diamond
Double-terminated, self-formed, and pulled from one small stretch of upstate New York — here’s what makes every piece in this family genuinely rare.
The story: About 500 million years ago, ancient seas laid down the dolostone of the Little Falls Formation across the Mohawk Valley. As the rock later cracked and shifted, silica-rich groundwater seeped into small open pockets and crystallized slowly — with nothing to attach to. That’s the whole secret: most quartz grows welded to a wall and only shows one finished point. A Herkimer diamond floats free in its pocket and grows a sharp termination on both ends, which is why even a small one already looks “finished” straight out of the ground.
Why collectors chase them: True double termination is uncommon in nature, and the exceptional clarity these crystals can reach — combined with a locality that exists nowhere else on Earth in this form — is what separates a “Herkimer” from ordinary quartz. Some carry smoky color, phantom growth lines, or tiny trapped inclusions, so no two parcels ever look quite the same.
Care: At Mohs 7, quartz shrugs off everyday handling, but those double points are genuinely sharp — store loose pieces so the terminations aren’t grinding against each other, and clean with a soft, dry cloth.
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