To date, there have been 34 designs for the official Olympic torch using materials ranging from the more common aluminium alloys or stainless steel, to silver-, copper-, and nickel-plated designs and torches made from varnished metals, wood, plastics and even glass. Early torches burnt olive oil or gunpowder.

• Vom Feuerstock zur Alu-Fackel,
  Peter Thomas,
  FAZ July 21, 2012.
  Link
• London 2012: Will the Olympic torch survive a British summer?
  Helen Bushby,
  BBC News April 19, 2012.
  Link
• The Olympic Torch Relay Facts & Figures,
  International Olympic Committee (IOC)

Also of Interest

• What Makes a Candle Flame?
  The different reaction zones of a candle flame and its heat and mass transfer pathways
• Chemistry of the Christmas Candle — Part 1
  Klaus Roth,
  ChemistryViews 2011.
  When we light a candle, the chemistry we are pursuing is not only especially beautiful, but also especially complex
  https://doi.org/10.1002/chemv.201000133