Brigham Young on Joseph's multiple seer stones in the Historian's Office General Church Minutes (April 1853).
Historian's Office General Church Minutes, 1853 April 17. CR 100 318, Church History Library
Josephs 1st seer stone ad O.C. one found well...
Joseph ad 3 which Emma 2 small ones . 1 large one
Richard Turley, Jr., Robin Jensen, and Mark Ashurst-McGee transcribe it this way: “I have Joseph[’]s 1st Seer Stone which I [h]ad from O[liver] C[owdery]...Joseph [h]ad 3 which Emma has...2 small ones and 1 large one.”
From "Joseph the Seer," Ensign (Oct. 2015): https://www.churchofjesuschrist.org/study/ensign/2015/10/joseph-the-seer?lang=eng