"Herkimer Diamonds" Gem-quality "Herkimer Diamonds" are hexagonal-shaped quartz crystals found in some of the surface bedrock of Herkimer, New York. Herkimer is located at approximately 43 north latitude and 75 west longitude. The oldest of these gemstones are believed to be approximately 500 million years old. These quartz crystals are magnificent works of nature that have a natural diamondlike geometric shape formed when the quartz. crystallized. Natural "Herkimer Diamonds" were not cut or shaped by humans. Due to their appear- ance, "Herkimer Diamonds" are commonly used in jewelry. These quartz crystals are not true diamonds. Mineral Characteristics of "Herkimer Diamonds" (Quartz) and True Diamonds Dominant Form of Chemical Mineral Color Luster Hardness Composition Breakage Colorless or variable "Herkimer Diamond" (quartz) SIO, Glassy 7 Fracture Colorless or variable True diamond Glassy 10 Cleavage Photographs of "Herkimer Diamonds" (Quartz)