Herkimer “diamonds” are not true diamonds but doubly-terminated quartz crystals, found loose in dolomite pockets around Herkimer County, New York. Because they grow without attaching to a matrix wall, they develop naturally pointed terminations on both ends and can reach unusually high clarity for quartz.
This parcel brings together roughly eighteen loose crystals and small clusters from the same New York locality, ranging from tiny gemmy points to larger golden-toned pieces with visible growth lines. It’s a good way to pick up a range of sizes and clarities from one find rather than a single specimen. At Mohs hardness 7 these are durable, but the sharp double terminations are worth handling with a little care.
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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