Continuing the discussion from Video of Coke cans being devoured by lava:
You are correct that aluminum does not change color as it is heated, but it most definitely burns. I worked as an union aluminum MIG and TIG welder for a few years. As a welder if you hold the heat in the same place for to long the aluminum just burns away. This is what is known as burn through. Thermite, a mixture of Aluminum and Iron Oxide three (rusted iron) leaves behind molten iron when ignited by burning off the aluminum and the extra oxygen in the iron. Many explanations of this can be found on YouTube.
Also: Aluminium is a silvery white metal. The surface of aluminium metal is covered with a thin layer of oxide that helps protect the metal from attack by air. So, normally, aulumium metal does not react with air. If the oxide layer is damaged, the aluminium metal is exposed to attack. Aluminium will burn in oxygen with a brilliant white flame to form the trioxide alumnium(III) oxide, Al2O3.