[Aztlan] Stele construction

[GK]

Hi all,
   
  I'm trying to find information on how stele were constructed during the classic period in Tikal (specifically around the 800's). Were they made with sandstone, rock or limestone? What was the manufacturing process? And how long did the process take? 
   
  If you know of any online resources that you can point me to that would be much appreciated. 
   
  Thanks, in advance...
   
  Gagan Kanwar

  Austin, TX