"Herkimer Diamonds" is the name given to the doubly terminated quartz crystals found in Herkimer County, New York and surrounding areas. Examples of these crystals are shown in the photos on this page. These crystals have the typical hexagonal habit of quartz; instead of having a termination on one end they are doubly terminated. This is a result of the crystals growing with very little or no contact with their host rock. Such doubly terminated crystals are very rare, and this is part of what makes Herkimer Diamonds so popular with mineral collectors.