Space shuttles don't use just one type of heat shielding.
The nose and wing edges are covered with a carbon composite material (carbon fiber reinforcement in a matrix of graphite with a silicon carbide coating).
The bottom is covered with silica fiber tiles made from very pure quartz sand with borosilicate glass coating (the remaining black parts that are not carbon composite).
The sides and top are made of same silica fiber tiles, but with aluminium oxide coating (the white parts).
Here a link for the carbon composite:
http://en.wikipedia.org/wiki/Reinforced_carbon-carbonThe silica tiles are essentially a type of glass fiber. Somebody else might know better if is there any chemistry involved in fiber extruding.