North America's two largest aquamarine gemstones came from Stoneham, Maine—a century apart.
AN EXCEPTIONAL AQUAMARINE CRYSTAL was found in a Stoneham pasture by Gilman McKeen while driving cattle in 1881 (Perham 1987). The broken crystal measured 12 × 5.4 cm. George Kunz purchased it, plus a second crystal found by another farmer elsewhere in the Stoneham area. He wrote, “In color and material, this is the finest specimen that has been found in any North American locality, and the crystals, unbroken, would equal the finest foreign crystals known” (Kunz 1892, pp. 92–93). North America's finest and largest aquamarine gemstone, a flawless greenish-blue 137.2-carat square cushion that measures 35 × 35 × 20 mm, was cut from that crystal (Bradshaw 2000). It is illustrated in Kunz (1892), Perham (1987), and King (2000) and can be seen at the Field Museum in Chicago.
Dr. Carl A. Francis is curator at the Maine Mineral and Gem Museum and an executive editor of Rocks & Minerals.
Myles Felch is staff geologist at the Maine Mineral and Gem Museum.
Alexander U. Falster is research technologist at the Maine Mineral and Gem Museum.
Douglas A. Bailey is collection manager at the Maine Mineral and Gem Museum.