Gore Mountain Garnet, found in the Adirondack mountains in New York, contains the world’s largest garnets. The rock that holds these garnets, garnet amphibolite, is sometimes referred to as ‘black ore’ or ‘dark ore.’ This rock formation formed during metamorphism during the Ottawan Orogeny, and extremely high temperatures combined with introduction of fluids is what most likely contributed to the unusual size of the megacrystic garnets.