From: Dictionary of American Naval Fighting Ships, Vol. III p 451

Iolite

A gem found in various shades off blue, with glassy luster and strong dichroism.

Iolite (PYc--41), a yacht, was built in 1914 as Florence D by Geo. Lawley & Son, Neponset, Mass. She was purchased by the Navy 4 September 1942 from Julian F. Detmer, of Tarrytown, N.Y., converted to Navy use and commissioned 9 November 1942, Ens. C. J. Symington in command.

Iolite sailed from New York via Norfolk and Miami 15 December 1942 and arrived Key West 22 January 1943 for duty at the Sound school. The converted yacht carried out training operations in the Straits of Florida, testing underwater sound equipment and monitoring techniques vital to submarine and antisubmarine warfare. She was detached from this duty in May 1944 and sailed for New York 28 May. Arriving Tomkinsville, N.Y., 14 June, the ship was placed in service 17 June for use as a training ship for reserve officers. She was badly damaged by explosion 26 August 1944 and placed out of service 2 October 1944. Stricken from the Navy List 14 October Iolite was transferred to the Maritime Commission in 1945 and sold.