When someone says that there is something made up of chrome, it means that there is a coating on the top of the metal. Just keep in mind that there is nothing fully made out of chrome. This kind of hard chrome coating can go on the top of different kinds of metal where the underlying metal could be aluminum, copper, brass, plastic or any others.
It is quite easy to get mixed up as people generally assume that hardchrome is something that gives shiny effect. The best way to find out if certain part is chrome plated or not, is by comparing the chrome plated part with the part of the metal that is having doubt to be chrome plated. The chrome plated part will be more reflective as well as brighter as compared to the other part which will reflect to be bluer.
Thus, this is how chrome plating is understood by its reflection.