The account of the men of King Limhi’s expedition finding the plates of gold (v. 11) is found in Mosiah 21:25–27 and Mosiah 8:7–12. This incident was previously discussed under those verses.
The two stones set in the bow are not mentioned again in the Book of Mormon until the book of Ether where Moroni tells us “the Lord commanded [the brother of Jared] to seal up the two stones he had received” (Ether 3:28). Moroni does not tell us from whom he had received the two stones. However, Mormon, his father, as he abridges the Nephite record tells us that they were handed down from generation to generation for the purpose of interpreting language (Mosiah 29:14). Apparently there was no further need of them between the time of Mosiah, son of Benjamin, and Moroni. The record was to be a warning to future inhabitants of the Americas (v. 15), and so were delivered to Joseph Smith for the purpose of translating the Book of Mormon record. Moroni, now an angel, described them to Joseph Smith before he was given them.
34 He said there was a book deposited, written upon gold plates, giving an account of the former inhabitants of this continent, and the source from whence they sprang. He also said that the fulness of the everlasting Gospel was contained in it, as delivered by the Savior to the ancient inhabitants;
35 Also, that there were two stones in silver bows—and these stones, fastened to a breastplate, constituted what is called the Urim and Thummin—deposited with the plates; and the possession and use of these stones were what constituted “seers” in ancient or former times; and that God had prepared them for the purpose of translating the book. [Joseph Smith—History 1:34–35]
Joseph describes his obtaining the record and the two stones and calls them the Urim and Thummim, the biblical name (see Exodus 28:30).
Having removed the earth, I obtained a lever, which I got fixed under the edge of the stone, and with a little exertion raised it up. I looked in, and there indeed did I behold the plates, the Urim and Thummim, and the breastplate, as stated by the messenger. The box in which they lay was formed by laying stones together in some kind of cement. In the bottom of the box were laid two stones crossways of the box, and on these stones lay the plates and the other things with them. [Joseph Smith—History 1:52]
The three special witnesses of the Book of Mormon were later given a promise of seeing the plates, the Urim and Thummim, and other sacred Nephite items if they were faithful.
1 Behold, I say unto you, that you must rely upon my word, which if you do with full purpose of heart, you shall have a view of the plates, and also of the breastplate, the sword of Laban, the Urim and Thummim, which were given to the brother of Jared upon the mount, when he talked with the Lord face to face, and the miraculous directors which were given to Lehi while in the wilderness, on the borders of the Red Sea.
2 And it is by your faith that you shall obtain a view of them, even by that faith which was had by the prophets of old.
3 And after that you have obtained faith, and have seen them with your eyes, you shall testify of them, by the power of God; [D&C 17:1–3]
The promise was fulfilled and their testimony of that experience is included in the front of every copy of the Book of Mormon.
The possessor of the sacred stones being called a seer (Mosiah 28:16) was again stated by Moroni when he appeared to Joseph Smith (Joseph Smith—History 1:35; quoted above). Apparently a seer may be given the keys, but may not be called upon to translate until or if there is a need. Today, the First Presidency and the Twelve Apostles are sustained as prophets seers and revelators, but none since Joseph Smith have needed to translate ancient records. However, when the time comes for the promised other records to be brought forth the keys are here. Also, the Nephites had prophets who were probably seers after the time of Mosiah, but there is no record of anything they may have translated. Since Alma was given the interpreters (Mosiah 28:20), it would seem that he was given the keys.