The term “brass” is used 116 times in the Old Testament of the King James Bible to translate the Hebrew term that means “copper” and can also refer to copper alloys (notably “bronze,” which came into use a millennium and a half years before Lehi’s time). Since the term was used in the Bible known to Joseph Smith, and whose language style he employed in his translation of the Book of Mormon, the argument about the copper/zinc alloy is pointless.
Of particular interest is the following passage from Ether 10:23, written by Moroni: “And they did work in all manner of ore, and they did make gold, and silver, and iron, and brass, and all manner of metals; and they did dig it out of the earth; wherefore, they did cast up mighty heaps of earth to get ore, of gold, and of silver, and of iron, and of copper.” Compare the two lists in this verse:
gold silver iron brass
gold silver iron copper
The lists are identical except for the last word, which is “brass” in the first list and “copper” in the second. Since the same Hebrew word is rendered both ways in the King James version of the Bible, this suggests that, in the Hebrew, the two lists are identical.