Emerald Lingam Emerald Lingam Emerald Lingams are established in many Hindu Temples in Tamil nadu. Emerald (Tamil: மரகதம்)is a variety of the mineral beryl (BeAl(SiO)) colored green by trace amounts of chromium and sometimes vanadium. The hardness of Beryl is 7.5–8 on the 10 point Mohs scale of mineral hardness. The toughness (resistance to breakage)of Emerald is classified as generally poor, hence most emeralds are highly included. Emerald is a green gemstone. Emerald means the shade of green color. Because of its green color, the term Emerald is employed. Emerald is also associated with the eighth planet Mercury in the Solar System.
USS Aquamarine (PYc-7) named for the gemstone aquamarine. Assigned to the Naval Research Laboratory, Bellevue, D.C., "Aquamarine" assisted in experimental work, chiefly underwater sound. Although most of her experiments were conducted on the Potomac River and Chesapeake Bay, she also operated off New London, Connecticut, from 16 October to 4 November 1943, and off the Florida coast and in the Bahamas from 24 January 1944 to 18 April 1945. During 1945 and 1946 "Aquamarine" had additional duty as special tender to the presidential yachts and . "Aquamarine" was decommissioned on 21 June 1946 and transferred to the Maritime Commission on 31 January 1947