Crystal Grottoes Caverns - The Gem Mill
Approximate — check official site before visiting
Fee-dig gem mining flume at Maryland's only show cave. Purchase bags of sand with gemstones, fossils, or treasures and sift through running water to discover minerals. Multiple bag options from $9 Small Gemstone to $35 Explorer Bag. Also offers arrowhead, seashell, and geode bags. The caverns offer guided tours March through November.
🪨 What You Can Find Here
Gemstones
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Fossils
From shark teeth in Florida to dinosaurs in Montana, the US offers world-class fossil hunting for all skill levels.
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Geodes
Hollow rocks lined with crystals. Iowa's Keokuk region is the Geode Capital of the World.
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Crystals
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Pyrite
Iron sulfide known as Fool's Gold for its metallic luster. Found in many US states, often in association with other minerals. Popular with beginner collectors.
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📍 Nearby Locations in Maryland
Calvert Cliffs State Park
Lusby, Maryland · State Park
World-famous Miocene fossil site. Collect fossil shark teeth (megs), shells, and marine mammal bones along 15 miles of Chesapeake Bay shoreline.
Flag Ponds Nature Park
Lusby, Maryland · County Park
Excellent Calvert Cliffs fossil hunting site. Shark teeth, ray plates, and marine mammal fossils on Chesapeake Bay beaches.
Potomac River Fossil Beds
Accokeek, Maryland · Public Land
Cretaceous fossil deposits along the Potomac River. Dinosaur teeth, bones, and plant fossils can be found in the eroding banks.
Clark's Elioak Farm - Gem Mining
Ellicott City, Maryland · Fee Dig
Gem mining flume at a historic petting farm in Howard County (operating since 1797). Purchase a bag of Mine Rough in the Castle Store and use the runn...
Dinosaur Park
Laurel, Maryland · County Park
Active paleontological dig site and public park in Prince George's County preserving Early Cretaceous fossils (110 million years old). Free Open House...
⛏️ Recommended Gear
Make the most of your visit to Crystal Grottoes Caverns - The Gem Mill with the right equipment.
Rock Hammer
The most essential rockhounding tool. Choose a hammer with both a flat striking face and a pointed pick end.
Typical: $25-45
Safety Glasses
Mandatory protective gear. Rock chips fly unpredictably when hammering.
Typical: $10-20
Chisel Set
Cold chisels in 3-4 sizes for precise extraction from matrix rock.
Typical: $15-30
Geologist's Pick
A heavier crack hammer for splitting hard rock. Essential for hard rock mining areas.
Typical: $35-60
Sifting Screen
Stackable mesh screens for sifting gravel and dirt. Essential for gem and fossil hunting.
Typical: $20-40
UV Flashlight
Long-wave UV light for finding fluorescent minerals and Yooperlites.
Typical: $15-35