Last week I posted the following question here: https://www.physicsforums.com/printthread.php?p=2735375 "Is it possible to predict the color of a solid object based on its molecular formula?" It wasn't completely ignored but the thread did come to an abrupt end after only three responses, so I was wondering if I should have posted it in this section instead of the "general physics" section. Basically I want to know why an object is whatever color it is. For example, to my left is a green box of tea. When white light hits it, green photons are reflected while other photons are absorbed. Why? I know that the electrons in an isolated atom have distinct energy levels and absorb only photons which can change their energy from one allowed level to another, but what about the case where there is a solid or liquid mix of atoms or molecules? Is the theory behind this established enough so that one say, "given a solid made of these particular molecules at this particular temperature, we know that it will be green"?