Joel Tiffany records Martin Harris as giving vivid descriptions of the seer stones that Joseph used to translate the BOM.

The following narration we took down from the lips of Martin Harris, and read the same to him after it was written, that we might be certain of giving his statement to the world. . . . “The two stones set in a bow of silver were about two inches in diameter, perfectly round, and about five-eighths of an inch thick at the centre; but not so thick at the edges where they came into the bow. They were joined by a round bar of silver, about three-eighths of an inch in diameter, and about four inches long, which, with the two stones, would make eight inches.” “The stones were white, like polished marble, with a few gray streaks. I never dared to look into them by placing them in the hat, because Moses said that ‘no man could see God and live,’ and we could see anything we wished by looking into them; and I could not keep the desire to see God out of my mind. And beside, we had a command to let no man look into them, except by the command of God, lest he should ‘look aught and perish.’”See Full