Large Hematite Genuine stone on Nickel silver Engraved base Buckle. Approx. 3 “ w x 2 ½ ” h. Hematite is the mineral form of Iron oxide colored black to steel or silver-gray, brown to reddish brown, or red. Grey hematite is typically found in places where there has been standing water or mineral hot springs, such as those in Yellowstone National Park. The mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can also occur without water, however, usually as the result of volcanic activity.