Question

in general, is there a away to predict which medium has the most refraction jjust by looking at it (think about n- index of refraction)

Answer 1

if you have a fixed background, let's say a building and you are looking it partly drought the glass; how much light is bend when it comes to your eye relative to the empty air?

but in general without seeing how light behaves with it ? (naked eye maybe, but i don't know how and with electron microscope or röntgen or something which determines the crystal structure it would be possible, but what do you need to know from components itself ? )