You can go rockhounding for herkimers at the herkimer diamond mines in New York. They have a campsite and a local retail shop.
Herkimer diamonds, discovered in the 18th century, are double-terminated quartz crystals discovered in Herkimer County, New York. The diamond in their name refers to natural faceting and clarity, they are not diamonds. Double-point quartz are plentiful and found in many sites around the world in all shapes and sizes.
Wash in warm soapy water. Can use a soft bristled tooth brush to clean.