Nelson Mandela speaks to the media after he presented US President Clinton with a rock quarried from the mine at Robben Island (where Mandela was made to work for many years). He included a certificate, personally authenticating the quarried rock.
White House Television crew
CC BY-SA 4.0
Clinton Presidential Library <a rel="nofollow" class="external free" href="https://www.youtube.com/watch?v=ndPrtbWCwVM">https://www.youtube.com/watch?v=ndPrtbWCwVM</a>