According to John Tvedtnes, in the Book of Mormon we find that records were frequently kept on metallic plates. This was done not only with Mormon's abridgment, but also with the small and large plates of Nephi, the brass plates obtained from Laban, the records kept by the people of Limhi (see Mosiah 8:5), and Ether's twenty-four gold plates comprising the Jaredite history.
One of the authors of the Book of Mormon, Jacob (son of Lehi), explained why the Nephites kept their secret records on metallic plates: "I cannot write but a little of my words, because of the difficulty of engraving our words upon plates," he declared, but "we know that the things which we write upon plates must remain" (Jacob 4:1).
According to John Tvedtnes, a prominent late-nineteenth-century critic of the Book of Mormon wrote, "No such records were ever engraved upon golden plates, or any other plates, in the early ages." Tvedtnes writes that had this critic known Hebrew, he would have found an answer to the contrary in his own Bible. Isaiah 8:1 speaks of writing on a polished metal plate with an engraving tool, however the terms are mistranslated "roll" and "pen" in the King James Bible. Tvedtnes also writes that the critic seems to have been unaware of the fact that the Apocrypha, which was included in about half the King James Bibles in the early nineteenth century, notes that a treaty between the Jews and the Romans in the second century B.C. was inscribed on bronze plates (see 1 Maccabees 8:22).
In recent years, scholars have come to realize that the concept of preparing records that would last through many centuries, making them available to later generations, is ancient. Records written on clay (a common practice in what today constitutes the nations of Iraq, Syria, and Turkey) were sometimes baked to make them last longer and were occasionally kept in containers. Documents written on papyrus and parchment, which are considerably more perishable than clay, were often preserved in pottery jars or in tombs. Another method the ancients used to preserve documents was calling on divine guardians to keep the records safe.
Writing on metallic plates was yet another way to ensure the durability of records. Many of the metallic records discovered to date have been found in foundation deposits, often in stone boxes, as was the Book of Mormon. These include records left behind by Sumerian, Hittite, Assyrian, Babylonian, and Persian kings, as well as foundation deposits from other parts of the Near East and from Asia.
Of all the metals, gold is the one least likely to decay over time. It does not oxidize like iron, silver, copper, or its alloys (bronze and brass); and it does not wear down like lead. Because it is a softer metal, it is easier to engrave, yet unlike lead, which is softer still, it does not readily lose its shape. Consequently, the most durable records would have been written on gold or gold alloy plates and hidden away in stone boxes, which are less likely to degrade than pottery. [John Tvedtnes, The Book of Mormon and Other Hidden Books: Out of Darkness unto Light, pp. 148-151] [See 2 Nephi 18:1]