Who discovered diamond and graphite? And when was it?

Question: Who discovered diamond and graphite? And when was it?
- Keywords:
  diamond,
  graphite
Asked by 256bmay33 to Peter, Jonathan, Grace, Doris, David, Ann on 31 May 2019.
- Peter Macharia answered on 31 May 2019:
  
  Diamonds: 1867 a 15-year-old Erasmus Jacobs found a transparent rock on his father’s farm, on the south bank of the Orange River in South Africa
  
  Graphite was first discovered in Cumbria in northern England at the beginning of the sixteenth century
- Grace Kago answered on 4 Jun 2019:
  
  Earliest discoveries of diamond are apparently all the way in 4th century BC from India apparently. In Africa, I think they were found in South Africa in the 1800s.
  Source: https://www.cbsnews.com/news/diamonds-a-history/
  Graphite: 1500s in Cumbria, England
  https://www.newworldencyclopedia.org/entry/Graphite

Question: Who discovered diamond and graphite? And when was it?