..... same energy levels of electrons as in glass. What would it take to change the eV levels of the electrons in the solid opaque matter, to the same energy levels of the electrons in glass. There is nothing necessarily special about glass, it is just a combination of silicon, sodium, and calcium atoms arranged in such a way that the electrons do not absorb visible light. It takes more eV from em waves to get absorbed, like ultraviolet will get absorbed, but visible light will not, in glass. Physicists say the absorption, and emission lines for solids are too discernable, or just do difficult to get, because these can be a variety of different elements in a block of matter. Heating a opaque block of matter can get the electrons to higher shell levels, but how much heat would it take. If you combined microwaves to pass throughtbthe opaque matter to heat the matter up, with heating the opaque matter from another source of heat. Could this also raise electrons in the opaque matter to energy levels/shell levels that do not absorb visible light. I am grateful for your help anything helps even a few words.