Joseph describes plates as "plates of gold."
Joseph Smith, History, circa Summer 1832, p. 4 The Joseph Smith Papers website, accessed August 11, 2021
[A]n angel of the Lord came and stood before me and it was by night and he called me by name and he said the Lord had forgiven me my sins and he revealed unto me that in the Town of Manchester Ontario County N.Y. there was plates of gold upon which there was engravings which was engraven by Maroni & his fathers the servants of the living God in ancient days and deposited by th[e] commandments of God and kept by the power thereof.