The world's largest garnets come from Gore Mountain of the Adirondack Mountains in New York State.
The Adirondack Mountains and its garnets were formed during the Ottawan period of the Grenville Orogeny, which was a long mountain-building event that occurred 1,050 million years ago. During this time, extremely high temperatures and an introduction of fluids from faults likely caused the abnormally large size of the garnets.
Gore Mountain is located in the southern part of the Adirondack Mountains in Warren County. Barton Garnet Mine was established in 1878 when entrepreneur Henry Hudson Barton started turning garnet into sandpaper abrasive in post-Civil War America.
The dark rock surrounding the garnets is called garnet amphibolite, or "black ore."
Type: Garnet Locality: Gore Mountain, Adirondacks, New York
