Bruce R. McConkie
"Joseph Smith received the same Urim and Thummim had by the Brother of Jared for it was the one expressly provided for the translation of the Jaredite and Nephite records. (D. & C. 10:1; 17:1; Ether 3:22-28.) It was separate and distinct from the one had by Abraham and the one had by the priests in Israel. The Prophet also had a seer stone which was separate and distinct from the Urim and Thummim, and which (speaking loosely) has been called by some a Urim and Thummim. (Doctrines of Salvation, vol. 3, pp. 222-226.)
"President Joseph Fielding Smith, with reference to the seer stone and the Urim and Thummim, has written: ’We have been taught since the days of the Prophet that the Urim and Thummim were returned with the plates to the angel. We have no record of the Prophet having the Urim and Thummim after the organization of the Church.’ (Mormon Doctrine, p. 818)