From the Wikipedia article on the Golden Plates:
According to Latter Day Saint belief, the golden plates (also called the gold plates or in some 19th-century literature, the golden bible) are the source from which Joseph Smith claimed to have translated the Book of Mormon, a sacred text of the faith. Some witnesses described the plates as weighing from 30 to 60 pounds (14 to 27 kg), golden in color, and composed of thin metallic pages engraved on both sides and bound with three D-shaped rings.
Witness Descriptions of the Gold Plates
This article published by Journal of Book of Mormon Studies 10/1 (2001) collects the testimony of many witnesses regarding the physical characteristics of the golden plates. Not all of the descriptions are completely consistent, but together they can help to build an idea of what the golden plates would have looked like.
As Depicted in Book of Mormon AR
Page dimensions: 6 inches wide by 8 inches high by 0.016 inches thick with each plate taking up 0.0334 inches in the stack, which makes for about 30 plates per inch in the stack. The extra space for each plate is meant to account for the plates not being perfectly flat.
Total dimensions: 6 inches by 8 inches (the dimensions of each plate) and 6 inches worth of plates. One third of the plates are unsealed, which comprise the Book of Lehi (the source for the lost 116 pages of the original manuscript) and the existing text of the published Book of Mormon. Two thirds are sealed, as per some witness accounts.
The sealed portion: No witnesses described the sealed portion as bound by metal bands, but this is how artists have typically portrayed them. David Whitmer said: “What there was sealed appeared as solid to my view as wood.” Book of Mormon AR has an option to display the sealed portion with metal bands or as enclosed by some kind of a solid. An artist who made a replica of the gold plates for the LDS Church History Museum used beeswax and pitch to make up the solid encasing of the sealed plates. The creators of Book of Mormon AR used the same technique to come up with the texture for the solidly encased sealed plates.
Characters: For Book of Mormon AR, characters were copied from the “Anthon Transcript” to provide for the engravings on the 3D model. A verse in the Book of Mormon explains the text was written on plates of ore in “reformed Egyptian”.