Ace of Diamonds Mine

Arguably one of the most prolific mines in Herkimer County, Ace of Diamonds Mine has continuously been a premier locality for the world-famous Herkimer Diamond quartz crystals. Located in Middleville, right next door to it's main competitor, the Herkimer Diamond Mine, it has been a fixture of the Upstate New York mining scene for decades. In February of 2024, it was announced that the mine would be closed indefinitely due to ongoing and unresolved litigation. While there is hope it will reopen in the future, the mine has remained closed through the 2025 mining season.

A lightly smokey doubly terminated Herkimer Diamond quartz specimen with excellent clarity and small inclusions of black hydrocarbons.