Today most aquamarines come from Brazil; these stones are typically a bluish-green and are therefore typically heat treated. Aquamarines are also found in Tanzania, Nigeria, Sri Lanka, Kenya, Afghanistan, and Russia. The largest known aquamarine was found in Brazil in 1920. The crystal measured 19 inches by 16 inches and weighed 243 pounds. Eventually this giant specimen was cut into gemstones. One 13 pound uncut portion of the stone is kept in the American Museum of Natural History in New York City. In the British Museum of Natural History in London a bluish-green, flawless aquamarine of 879.5 carats can be found.