Despite commonly being called Herkimer Diamonds, this mineral is actually a type of quartz. It's named after Herkimer County in central New York State where it is mined. The most defining features of the Herkimer Diamonds are their doubly terminated crystals, incredible clarity, and interesting inclusions.
Herkimer Diamonds were formed in the Cambrian Age nearly 500 million years ago. They formed when vugs (small cavities inside rock) formed inside of Dolomite, a mineral similar to Limestone. These vugs would then fill with organic compounds such as hydrocarbons (a compound used to make petroleum and natural gas) as well as silica, which is what crystals are formed from. They get their unique, short doubly terminated shape because the crystals had little to no contact with the Dolomite while forming and thus were able to grow in two directions. Similar double terminated Quartz have been found in Arizona, Afghanistan, Norway, Ukraine, and China, but they can only be called Herkimer Diamonds if they came from Herkimer County.
They were discovered long ago by the Mohawk Indians, who could find them in streams or while plowing. They used the crystals as amulets, in tools, and to trade with other tribes, but their popularity began to wane when glass beads were introduced from Europe in the 17th century. Since they are quartz, they have the same properties as other Quartz such as a hardness of 7 and hexagonal crystal structure. They are often small, ranging from microscopic to six inches in length, though most are under an inch long. They usually have a brilliant clarity because their crystals grew rather slowly, however, they can occasionally have a smoky coloring. But you may be wondering, what are all those little black specks found in so many Herkimer Diamonds? Well, in many cases, those are inclusions of solid hydrocarbons, but Herkimer Diamonds can also contain inclusions of Calcite, Dolomite, Pyrite, Sphalerite, Coal, fossilized plant material (formerly known as Anthraxolite), tinier Herkimer Diamonds, as well as liquid petroleum, and carbon dioxide. The rarest and most prized Herkimer Diamonds are Enhydro Herkimers which have water trapped inside that is millions of years old!
They have some amazing metaphysical properties including the following:
* Magnifies the influence of other stones
* They are a great healing stone
* Being connected to the crown chakra they can help us create a high spiritual vibration
* Boosts clairvoyant abilities