Hyde reprints Pratt's description of the plates.
Orson Hyde, Ein Ruf aus der Wüste (A Cry out of the Wilderness) (Frankfurt: Im Selbstverlage des Verfassers, 1842), 25–26, extract, English translation, The Joseph Smith Papers website, accessed August 11, 2021
These were engraved on uniform plates which had the appearance of gold. Each plate was almost 7 inches wide and almost 8 inches long and in thickness somewhat less than common tin. They were engraven with a fine script similar to Egyptian hieroglyphs and fastened together in the form of a book by three rings, which were drawn through the whole by means of small holes on the ends. The entire book was approximately 8 inches thick and one part of it was sealed. The characters or letters of the unsealed part were small and artistically beautifully engraved (according to the words of Mr. [Orson] Pratt, from whose writings I have taken the foregoing account).