“Herkimer Diamonds are my Best Friend” - Tiffany DeVon

Herkimer Diamonds became widely recognized after workmen discovered them in large quantities while cutting into the Mohawk River Valley Dolomite in the late 18th Century. 

Geologists discovered exposed Dolomite in Herkimer County, outcroppings and began mining there, leading to the "Herkimer Diamond” Moniker.
These Double Terminated point Quartz Crystals are mined in Herkimer County New York, Hence, The Herkimer Diamond.

Herkimer Diamonds are 7.5 Mohs scale of hardnes and will cut glass even thou they are a bit softer than Diamonds. 

Herkimer Diamonds do not break or chip as easy as Diamonds they have 3 planes of cleavage to break along!

 
The Mohawk Indians and early settlers found Herkimer Diamonds in streams nesr sediments and plowed fields, an

"immediately held them in high esteem."

The Indians used amulets, to make tools and traded with other tribes until the early 1600’s.
Herkimer Diamonds  share many phyaical properties attributed to quartz. They are almost always transparent and range from colorless ("water clear") to smoky black.

These ancient souvenirs,  often have inclusions (material trapped in a mineral during formation). Solid hydrocarbon materials add a dark, sooty color; liquid inclusions of saltwater or petroleum, gaseous inclusions of carbon dioxide, or even other minerals, like dolomit, calcite  or tinier Herks,