Heavy Metal: Post #2 February 1, 2015

A lot of ridicule has been directed at Joseph Smith and his “gold Bible”.  When people weren’t trying to steal the plates from Joseph, they were busy making fun of such a silly story.  Gold plates indeed.

You hear less about the silliness of the gold plates today.  Ancient writing on metal plates is now well known.  So the critics today don’t talk about the silly gold plates so much.  But neither do they or their intellectual offspring seem to retract and repent of their former accusations. It makes you wonder about their honesty. If I had falsely accused someone, and if I were honest, I would retract my accusations and apologize.  If I didn’t, what would that say about my honesty and integrity?

I have seen the same pattern over and over again: ridicule, followed by supporting evidence followed by silence on the part of those who did the ridiculing in the first place.  Hmmm…

This link provides a really good summary of the use of metal plates in antiquity.


In particular, the pious Jewish people who wrote and buried the Dead Sea scrolls engraved their most important information on a rolled piece of copper.  So pious Jews like Lehi and his family could also have written on metal plates.


As I was learning about Joseph Smith in the late 1960s I never had any problem with “gold plates” story.  It seemed reasonable to me that if I had something really important to record, and I lived in central/south America, a place full of metals of all kinds, I would write these important records on metal.

So, no problem with writing on “gold plates”.

I had two other problems with the story, however.  First, if the plates were pure gold, they would be very heavy. Wouldn’t it have been hard, or nearly impossible, for Joseph (and Moroni) to lug around several hundred pounds of gold?  Second, pure gold is really soft.  It would not be a good metal to write on simply because any engravings would tend to rub against each other and wear down over time.

Since I knew the Book of Mormon was true, I put these questions on my mental “shelf” along with my zillions of other questions and kept looking for information.  As He has done before, God gave me the information I was seeking…almost 40 years later.

First question answered:  We have testimony now that the plates weighed from 40 to 60 pounds, were about 8 inches long and 7 inches wide. We also know that they were about as thick as parchment, and not quite as thick as common tin.


Finally, we know that about 2/3 of the plates were sealed. So the Book of Mormon was written on roughly 20 pounds or so of thin metal plates.

Does this make sense at all?  I did some calculations to find out.

Assuming the plates were 8 inches by 7 inches and about 1/32 of an inch thick, (I haven’t been able to find out how thick parchment or common tin were in the 1830s…and would welcome more information on this point), and assuming they were pure gold (density 1206 pounds per cubic foot), each plate would weigh about 1.22 pounds.  Twenty pounds of plates would allow you 16 separate plates, or 32 sides for engraving if engraved on both sides.  My English copy of the Book of Mormon is 531 pages long.  That’s a lot of pages to get into 16 plates engraved front and back.  Each side would be roughly 8 inches by 7 inches equals 56 square inches or 0.389 square feet or 12.4 square feet in which to write the whole Book of Mormon.

Hmmm… is it possible?

Well, my English copy of the Qu’ran has 640 pages.   Why the Qu’ran (Koran)?  The Koran is written in Arabic, a Semitic language, like Hebrew.  Hebrew and Arabic do not use any vowels or punctuation.  In the Book of Mormon, the prophet Moroni (see Moroni 9:32-33) informs us that they wrote the book in characters they called “Reformed Egyptian”, but there is no reason to believe they had changed the basic structure of their written Hebrew language, only that they used a very compact set of characters with which to write the Book of Mormon.

I visited Moslem friends in Kuala Lumpur, Malaysia a few years ago. They took me to see a wonderful museum on Islam.  While there I saw a beautiful painting with the entire Koran in small but highly readable script.  Here is a picture of me standing alongside this painting (the batik shirt I am wearing is a gift from these generous people—more about them and about Islam in another post, another day).

Bruce Dale with painting of the Koran
Bruce Dale with painting of the Koran

The entire text of the Koran is painted in the golden inner area of the overall painting and measures about 4 feet high by 8 feet wide, or 32 square feet, minus the large script inside and the four circular decorations.  I estimate these reduce the area by about 4 square feet, or 32 minus 4 equals 28 square feet in which to write the entire Koran.  By proportion with the Book of Mormon that would be 531/640 times 28 square feet equals 23.2 square feet in which to write the Book of Mormon, compared to my estimate of 12.4 square feet in 16 plates given above.

That’s close enough for this engineer.

However, if the plates were a bit thinner than 1/32 of an inch, or if Reformed Eqyptian were even more compact than what this painter of the Koran was able to achieve with his brush and ink, or if the plates were not pure gold but rather some less dense metal, the agreement would be even closer.

Second question answered:  But the Book of Mormon plates were almost certainly NOT pure gold. They were probably an alloy of gold and copper and therefore less dense than pure gold.

That brings me to my second question referred to above—gold is just too darn soft for writing a permanent record. My dad was a mining engineer, and I grew up in (copper) mining towns in Nevada and Arizona. I loved rocks and minerals and, as a kid, I stuffed my head with facts about all kinds of rocks, gems, minerals and precious metals like gold and silver.  I knew that gold was a very soft metal and surely would not be a good choice for writing.  Just rubbing pure gold plates against each other would over time obliterate the engravings. That bothered me a bit, but I kept the question on my mental shelf and kept looking and thinking.

But Joseph never said the plates were pure gold. (I don’t think he cut off a piece and took it to the local chemist for analysis.  :))  He said they had the appearance of gold.

About a year ago, I was reading “Remembering Joseph, Personal Recollections of Those Who Knew the Prophet Joseph Smith” (wonderful book!) and came across something that I had never heard before in all my church activity over many decades.  Apparently Joseph Smith told his brother William that the Book of Mormon plates were a mixture of copper and gold.   (See William Smith, “The Old Soldier’s Testimony” Saints’ Herald 31. No 40 (4 October 1884): 643-44).

It turns out that the Mesoamerican people worked extensively with an alloy of copper and gold that the Spanish conquistadores called “tumbaga”. The Book of Mormon setting was probably Mesoamerica. Here is an article on tumbaga that is very interesting.


Here is a snippet about some relevant properties and composition of tumbaga from the Wiki article.

“Tumbaga is an alloy composed mostly of gold and copper. It has a significantly lower melting point than gold or copper alone. It is harder than copper, but maintains malleability after being pounded. Tumbaga can be treated with a simple acid, like citric acid, to dissolve copper off the surface. What remains is a shiny layer of nearly pure gold on top of a harder, more durable copper-gold alloy sheet. This process is referred to as depletion gilding.”

I saw a good bit of tumbaga in my visit to Colombia in South America a couple of years ago.  It looks a lot like gold to me.  I would certainly have said it has the “appearance of gold” like Joseph Smith said.

Importantly, tumbaga melts at a lower temperature than either pure gold or pure copper…so it would be easier to melt and cast into plates. It is also malleable (can be beaten into thin sheets).  It is harder than copper, therefore a lot harder than gold, and therefore much more resistant to abrasion.  Question answered!  (After 40 plus years…it pays to be patient.)

One other point before closing this rather lengthy post.  The Book of Mormon prophesies that it will shine forth out of darkness.


If the Book of Mormon plates were made of tumbaga that had been engraved and then treated by “depletion gilding” (see above), the engravings would have “shine(d) forth” as prophesied.

I testify that the Book of Mormon does shine forth as a bright testimony of Jesus Christ in these days of darkness.  I further testify that God does give knowledge to us if we keep the doors open and keep seeking.

Update August 14, 2015

In reading Richard Anderson’s book “Examining the Book of Mormon Witnesses” I learned (page 131) that John Whitmer, one of the witnesses, said that the plates were engraved on both sides.  So I will assume that both sides of the sheets of tumbaga could be engraved.  In reading John Sorenson’s book “Mormon’s Codex” I found (page 340) that Mesoamerican craftsmen could produce high quality metal sheets 0.2 millimeters thick by successive hammering and annealing.  So I will assume that the sheets on which the Book of Mormon was engraved were 0.2 millimeters thick or 0.00787 inches thick.  Furthermore, I decided to assume that the plates were a mixture of 50% copper and 50% gold, so that the density of the material would be the average of the density of gold and that of copper, or 1206 plus 559 divided by 2 equals 883 pounds per cubic foot.

With those new numbers, how many square feet of surface would be available for engraving the Book of Mormon?  Well, each plate (8 inches tall by 7 inches wide by 0.00787 inches thick) would weigh 0.225 pounds. Assuming again 20 pounds of plates for the unsealed part of the book, that is about 89 sheets. Each sheet would have two sides for engraving, so there would be 8 x 7 x 2 equals 112 square inches or 0.778 square feet per sheet or 69.2 square feet total for both sides of the 89 sheets.  I estimated above, based on the text of the Koran, that somewhere around 23 square feet would be required to engrave the Book of Mormon. So my two estimates of 12.4 square feet and 69.2 square feet nicely bracket the 23 square feet figure.

Oh that clever kid.