"Herkimer diamonds" are distinctive doubly terminated crystals of quartz from the Cambrian limestones near the town of Herkimer, New York. I dug up this specimen at the Herkimer Diamond Mine as a child.
Bubbles and black organic inclusions are common in these crystals. Inclusions make a stone worthless as a gem, but they are valuable scientifically, being samples of the fluids that circulated in the rocks at the time the crystals were being formed.
It's a real thrill to dig for Herkimer diamonds, no matter what age you are. And studying the faces and angles of the crystals will give you an appreciation of their appeal to mystics and to scientists, both of whom take crystal form as a tantalizing clue to the true nature of matter.
