All you have to do to determine the metal composition is flick it in the air with your thumb like you're doing the ole "heads or tails" gig. You will get the same sounds as you would from a hard surface, but without the dings.
One thing most, with such suggestions forgets is the largest amount of coin collectors are rather on the older side. Like me, I'm afraid. In case any younger people here haven't noticed how many times us older people say things like "HUH, what did you say?". The reason is we are not as good as we used to be with vision and hearing. If we have problems with hearing the normal sounds, what do you think it's like trying to differentiate a ringing sound between coin metallic sounds?