I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book. Joseph Smith, History of the Church, 4:461
The Book of Mormon doesn't say what ziff is, but whatever it was, King Noah put a 20% tax on it.
He [King Noah] laid a tax of one fifth part of all they possessed, a fifth part of their gold and of their silver, and a fifth part of their ziff. Mosiah 11:3
And he decorated his building with it.
King Noah built many elegant and spacious buildings; and he ornamented them with fine work of wood, and of all manner of precious things, of gold, and of silver, and of iron, and of brass, and of ziff. Mosiah 11:8: