This is a beautiful A grade Herkimer Diamond crystal. It has excellent clarity, double terminations and clean facet lines.
Additionally, a small window facet is present (needs to be viewed with a loupe).
Herkimer Diamond crystals are unique to the Mohawk Valley, New York state. Not much is know about native uses of the Herkimer's; but surely they were considered special.
Dean Snow, one of North America's leading historical anthropologists, in his book on the Iroquois writes:

"They were known to themselves and to the other Iroquois nations as the Kanyenkehaka, the people of Kanyenke (also spelled Ganienkeh). This has usually been translated "Place of the Flint," but the flint (or more properly chert) sources in Mohawk country were not particularly sought after. More important were the clear quartz crystals now called Herkimer diamonds, which could be quarried in a few local mines and abound on Mohawk village sites. These were highly valued by Iroquois and other nations. Kanyenke was more likely "Place of the Crystals." Crystals were symbolically important as amulets of success, health, and long life, artifacts more likely to inspire a name than a second-rate chert. The Mohawks were the main suppliers of quartz crystals up to 1614. After that they became primary middlemen for the Dutch glass beads that replaced them."
However, thousands of years later the Mohawks collected and traded quartz crystals, and placed them in burial sites, indicating their spiritual significance. In ancient times those who lived there were called the “people of the place of the crystals.”

A quality A grade Herkimer Diamond crystal.