Mineral site, and from there further subdivided by the chemistry of the W site. The Y and Z sites can accommodate a variety of cations, especially various transition metals; this variability in structural transition metal content gives the tourmaline group greater variability in colour. Other cyclosilicates include beryl, AlBeSiO, whose varieties include the gemstones emerald (green) and aquamarine (bluish). Cordierite is structurally similar to beryl, and is a common metamorphic mineral. Sorosilicates, also termed disilicates, have tetrahedron-tetrahedron bonding at one oxygen, which results in a 2:7 ratio of silicon to oxygen. The resultant common structural element is the [SiO] group. The
USS Aquamarine (PYc-7) for disposal. She was sold to Colonel E. M. Grimm of Columbus, Ohio, in 1947, and her name changed back to "Seawolf". She was sold in 1954 to Ennolls A. Stephens of Irvington, Virginia, owner of The Tides Inn, Irvington, and renamed "Miss Ann". In 2008, "Miss Ann" was sold to private interests who placed her in Charter Service on the Potomac River. In 2014, she is located at the Colonial Beach Yacht Club in Colonial Beach, Virginia. USS Aquamarine (PYc-7) USS "Aquamarine" (PYc-7) was a patrol boat in the United States Navy during World War II. Later known as