i have another one that is bronze from 1943 also but is this one silver. And what is that metal on the sides I actually pretty much know it's silver because it says 720 but just wanted to make sure
Looks like its the silver design of that year; the metal on the sides is likely solder (from being in a jewerly setting?) http://www.ngccoin.com/price-guide/world/mexico-20-centavos-km-438-1920-1943-cuid-1747-duid-8437
But isn't sterling silver 925 this is 720 I know it's silver now but its so cool that I keep looking at it
Right, it is Silver 0.720 fineness not Sterling Silver 0.925 fineness If you go to this link & go down to Silver you can see some different fineness of silver used: http://en.wikipedia.org/wiki/Millesimal_fineness
