From: Dictionary of American Naval Fighting Ships, Vol. IV p 231

Marcasite

Any of several minerals possessing a metallic luster, especially that consisting of crystallized iron pyrites.

Marcasite (PY--28) was built as a private yacht by George Lawley & Son, Neponset, Mass., in 1925 ; purchased by the Navy from Generalissimo Rafael Trujillo of the Dominican Republic 2 February 1942 as the yacht Ramfis ; renamed Marcasite 10 February 1942 ; converted for Navy use by Tampa Shipbuilding Co., Tampa, Fla, ; and commissioned at Tampa 12 May 1942, Lt. Comdr. Leander Jeffrey in command.

After Fitting out and completing shakedown, Marcasite departed Tampa 22 May for duty in the Pacific with the Hawaiian sea frontier. Steaming via Key West. she served as convoy escort en route to the Panama Canal, and on 9 June made a depth charge attack against a suspected enemy submarine in the Caribbean. The patrol yacht departed Balboa 20 June ; reached San Diego the 30th ; and thence sailed for Pearl Harbor late in July.

Following arrival in August, Marcasite operated out of Bishops Point. She patrolled the approaches to Pearl Harbor, escorted merchant ships operating among the Hawaiian Islands, and occasionally steamed to Midway and back as escort for merchant supply ships. She remained in Hawaiian waters until transferred to duty with the northwestern sea frontier 2(1 June 1943.

Marcasite departed Pearl Harbor 13 July, arrived at Seattle 9 August, and served as a patrol and weather station ship of the Pacific Northwest. She carried out 3-week patrols at sea during the remainder of 1943 and into 1944. She arrived 'at Puget Sound Navy Yard 16 June 1944 and was placed in reduced commission 28 June. Marcasite decommissioned 5 October 1944 and was transferred te WSA for disposal. Her name was struck form the Navy list 14 October 1944. Sold 5 December 1944, she later operated under the names Commando and Westminster.