Several earlier posts here and here discuss evidence for Pre-Columbian swords in ancient Mesoamerica. Swords were an important weapon in the arsenal of Book of Mormon peoples. It is likely that most swords in the Book of Mormon did not have metal blades, but the text does indicate that some of the people of Jared and Lehi possessed rare metal blades. The earliest reference is found in the account of the Jaredite prince Shule who led a successful rebellion to overthrow his brother’s regime.
“And it came to pass that Shule was angry with his brother; and Shule waxed strong, and became mighty as to the strength of man; and he was also mighty in judgment. Wherefore, he came to the hill Ephraim, and he did molten out of the hill, and made swords out of steel for these whom he had drawn away with him; and after he had armed them with swords he returned to the city Nehor, and gave battle unto his brother Cohihor, by which means he obtained the kingdom and restored it to his father Kib” (Ether 7:8-9).
The deeds of Shule in the passage are portrayed as noteworthy. He is described as “mighty in judgment” (Ether 7:8). He is the one with the knowledge and skill to do this. “He did molten,” he “made swords out of steel,” “he . . . armed them.” Did he pass this remarkable skill on to others? The passage does not say. It is interesting, however, that the next generation is nearly wiped out by war (Ether 9:12) and that there is no subsequent mention of steel or steel swords in the Book of Ether. This could be an indication that “steel” technology among the Jaredites was rare or even subsequently lost? In periods of social anarchy, rare and valuable possessions would tend to be stolen and lost or perhaps destroyed (Ether 14:1).
Shule’s steel may indeed refer to carburized iron that he learned how to temper into effective weaponry, but in early modern English the word steel had a broader range of meaning than it has today, which included not only carburized iron, but also hardened copper alloys such as bronze. The Oxford English Dictionary notes that while steel was more often applied to carburized iron, it could also be applied to “an alloy of tin and copper,” that is, bronze. This is why early English translations of the Bible, Coverdale (1535), Cranmer (1540), Matthews (1549), Bishop’s (1568), and the King James Version (1611) rendered the Hebrew word for copper in Psalms 18:34 and 2 Samuel 22:35 as “steel” even though in today’s terminology it would be more appropriately rendered “bronze” (Frank Moore Cross Jr., and David Noel Freedman, “A Royal Song of thanksgiving: II Samuel 22 = Psalms 18,” Journal of Biblical Literature 72/1 March 1953: 31). “The translation `steel’ instead of `bronze’ which appears in the King James Authorized Version, originated with Kimhi, who interpreted nhwsh as `hard metal” (Steven Shnider, “Psalm XVIII: Theophany, Ephiphany, Empowerment,” Vetus Testamentum 56/3 2006: 394).
The other passage bearing on the question of Jaredite swords is the one describing King Limhi’s search party. Although, they did not find the land of Zarahemla, the search party found ruins of buildings and bones of the Jaredites along with the 24 gold plates of Ether. “And for a testimony that the thing that they have said are true . . . . They have brought swords, the hilts thereof have perished, and the blades thereof were cankered with rust” (Mosiah 8:10-11). The search party brought back the rusted sword blades and other artifacts “for a testimony that the things that they had said are true” (Mosiah 8:9). That could suggest that metal blades were thought to be rare or unusual.
The description of rusted sword blades could refer to rusted steel, although the passage does not identify the metal in question. At the present time no authentic archaeological specimens of carburized iron steel are known from Pre-Columbian America. Given, however, the broader range of meaning of the word steel in the language into which the Book of Mormon was translated, it is also possible that the blades described were bronze blades. At least two different kinds of bronze were known in Pre-Columbian Mexico, though known archaeological specimens date later than Book of Mormon times. It is currently thought to have been introduced from north-western South America (Dorothy Hosler and Guy Stresser-Pean, “The Huastec Region: A Second Locus for the Production of Bronze Alloys in Ancient Mesoamerica,” Science 257 (28 August, 1992): 1215-1220; Heather Lechtman, “Arsenic Bronze: Dirty Copper or Chosen Alloy? A View from the Americas,” Journal of Field Archaeology 23 1996: 477-514). If the Jaredite blades found by Limhi’s search party were bronze, the description of blades cankered with rust would be an apt description of the effects of “bronze cancroid” or “bronze disease.” Bronze disease is “the process of interaction of chloride-containing species within the bronze patina with moisture and air, often accompanied by corrosion of the copper allow itself” (David Scott, “Bronze Disease: A Review of Some Chemical Problems and the Role of Relative Humidity,” Journal of the American Institute for Conservation 29/2 Autumn, 1990: 193). In such cases, according to Jason Sanchez and Ken Harl, bronze objects develop a greenish color on their surface when exposed to “extremes of heat, humidity, acids, or environmental pollutions,” typical of “a region with relatively high humidity throughout the calendar year.” If left untreated, “it produces a remarkable disintegrating and destructive effect on the object it attacks . . . slowly reducing it to amorphous powder” (W. G. Wood-Martin, “The Copper Age in Ireland,” Ulster Journal of Archaeology 9/2 April 1903: 91). Bronze disease” according to Tonya Yirka, is the “equivalent to rust in iron-based metals, occurs when oxygen and chloride combine in a moist environment to make hydrochloric acid. This acid forms copper and tin chlorides which in turn break down the bronze. Uncontrolled, this process will eventually destroy the bronze.” This process has only been more or less recognized and understood for the past century or so. (Wood-Martin, “The Copper Age in Ireland,” 89; Scott, “Bronze Disease: A Review of Some Chemical Problems and the Role of Relative Humidity,” 193).
Given that such weapons were likely quite rare anyway, we would not expect that we would necessarily find surviving examples in an ancient trash heap, nevertheless, the Book of Mormon description of how such blades could corrode and perish is understandable.