Herkimer Diamonds are actually a double-terminated quartz crystal of exceptional hardness. Only crystals mined in Herkimer County, NY may be given the name "Herkimer Diamond". They are exceptionally hard minerals and feature a termination point on each end as well as sometimes feature an enhydro inclusion, which is a tiny pocket of water encapsulated in the stone. These are natural stones and may contain very slight imperfections. They produce extremely high vibrations and are considered to be powerful amplifiers of spiritual energy. Herkimer Diamonds are aligned with the Zodiac sign of Sagittarius and also with the Third Eye Chakra or Ajna.