I saw an example in the testbook question specifically related a material's color(not transparent) to its conductivities.
Saying that: the visible light's energy was in the range from 1.8eV to 3.1 eV, and the material's Energy band could be excited with a gap lower than 1.8eV, thus the visible light was absorbed.
However, the case was special and there were many transparent materials that had a high conductivities. But could we conclude certain sense to a solid such that we can have some guess about its electronic conductivities and from the lights/laser it absorbed/emitted?
(So that we don't have to run current through it.)