Sorry!  Herkimer Diamonds are not real diamonds.  Herkimer Diamonds are actually quartz crystals that are naturally formed with points on both ends of the crystal.  These crystals are somewhat rare because in order to form with these double points, the quartz must have very little contact with the surrounding rock while the crystal is being formed.  The term Herkimer Diamond can only truly be used with samples found in Herkimer County, New York, although double point quartz crystals have been found in other locations throughout the world. 

You can see a photo of some Herkimer Diamonds here.

For more great information on Geology, Rocks and Minerals check out the Mini Me Geology website and our Dig into Geology section for more great information, free project and experiment ideas and puzzles!