This photo illustrates the insulating properties of aerogel. The crayons on top of the aerogel are not melting, protected from the flame by a layer of aerogel.
What's so light that you can hardly feel it? What's used by NASA to trap stardust? What's used in skylights to add a little extra insulation? Aerogel, a smoky blue material made from extracting liquid from a gel. Typically, aerogel is made from a silicon gel, but it can be derived from other materials. The smoky blue colored is caused by Rayleigh scattering (the same phenomena that makes the sky blue as the light bounces off of the tiny particles inside). Aerogel is a rigid material that works as an insulator as shown in the picture. The crayons maintain their shape and don't melt despite the fact that the only thing separating them from the flame is a thin layer of aerogel.