We offer you brilliant “Herkimer Diamond” quartz crystals in an affordable & fun mining adventure!  Keep all you find; bring your own tools or rent ours.    There are picnic tables near the mines .  Call us for group rates.

Visit our rock & mineral shop for specimens and gifts from around the world!

Herkimer Diamonds are world-famous quartz crystals found only in specific locations in New York State.  These unusually clear, brilliant crystals began forming millions of years ago and are highly sought after for their exceptional beauty.

Digging for these diamonds at Crystal Grove Diamond Mine & Campground is a fun and enjoyable experience for all ages.  You don’t have to be an expert to prospect – a shovel, hammer, and chisel are very useful, but even small garden tools will work.   (Some rental tools are available.)  If “breaking rock” is not for you, sifting through the dirt and tailings piles may also reveal these stunning gems.

Five hundred million years ago, during the Cambrian era, much of eastern North America was covered by a shallow sea.  As the sand and muck at the bottom of the ocean metamorphosed into the sedimentary rock known as limestone, seawater trickled into holes and cracks in the rock, where the heat and pressure forced the minerals in the water out of solution, so that crystals began to grow inside the rock.  Over time, some crystals weathered out of the rock and can be found loose in the dirt, while others are still inside the cavities (“on matrix”) where they formed all those years ago.  You can find these beautiful specimens either way, it just depends on how hard you want to work.  The rock where all Herkimer diamonds formed is known technically as “Little Falls Dolostone”, a dolomitic limestone composed of magnesium calcium carbonate, and it’s hard-rock mining anywhere you go.
Serious rock-breakers will need large sledge hammers (8 to 20 lbs) and lots of chisels and pry bars.  More leisurely collectors can dig in the dirt pile with small garden tools such as rakes, trowels, shovels, and screens.  Tweezers and whisk brooms come in handy.  Either way, eye protection is important, and gloves and work boots are good also.
Large specimens tend to have internal fractures and dings; the gemmy crystals are more likely to be 1″ or less.

A Gem of a Place