Yellow crayons generally burn the fastest because of the type of color pigments used. The yellow color is produced by adding cadmium or zinc chromates, which transfer heat better than other colors, such as black.
The melting point of all Crayola crayons is around 105 degrees Fahrenheit, regardless of color. However, the consistency of the melted wax may differ depending on the density and amount of pigment used in creating each different colored crayon. The method used to melt crayons also affects melting times, as darker colors absorb light energy faster than lighter colors. Therefore, using a hot lamp may produce different results than using a hair dryer.