Gemstone few as one in a million atoms. These so-called impurities are sufficient to absorb certain colors and leave the other colors unaffected. For example, beryl, which is colorless in its pure mineral form, becomes emerald with chromium impurities. If manganese is added instead of chromium, beryl becomes pink morganite. With iron, it becomes aquamarine. Some gemstone treatments make use of the fact that these impurities can be "manipulated", thus changing the color of the gem. Gemstones are often treated to enhance the color or clarity of the stone. Depending on the type and extent of treatment, they can affect the
USS Aquamarine (PYc-7) USS Aquamarine (PYc-7) USS "Aquamarine" (PYc-7) was a patrol boat in the United States Navy during World War II. Later known as Miss Ann, the ship was listed on the U.S. National Register of Historic Places in 1998. "Aquamarine" was built in 1925 by Pusey and Jones Corporation, Wilmington, Delaware under the name "Siele", the private yacht of John H. French. In 1936 she was sold to Robert H. Wolfe, of Columbus, Ohio, and renamed "Seawolf". "Seawolf" was bought by the Navy on 13 January 1941, and commissioned on 9 April 1941, Lieutenant G. A. Lange in command. She was