The Upper Peninsula magnet measures 2.75 inches wide. The Lower Peninsula magnet measures 1.5 inches. Each of the Upper and Lower Kona Dolomite stones have a very strong rare earth magnet glued to the back. Kona Dolomite is an ancient rock found in Marquette, Michigan. The Kona Dolomite stone is between 2.1 to 2.2 billion years old. Because of the great age, and due to the many trace minerals present, Kona Dolomite comes in a wide variety of shades including pink, brown, yellow, cream, red and orange with shades of brown, cream, gray and black mottling, banding and lacing.