Master marbles generally show a 3/4 coverage with color compared to an Akro @50-50.
I will call this one an Akro Patch type (Hero?) and appreciate any other opinions.
Marble—On!!
Marble collectors used to call this marble a "Miller".
Big bucks for a minty one. Yours, in mint shape would have have delivered in a great way dollar wise.
Nice find--a good place-holder for anyone that collects these.
Marble--On!!
The first one is a Rainbo my marble collecting friend--a very nice one.
The second one is a MCS or multi colored swirl--another nice one.
You can alway get more opinions from @Ric @Chad G. or @Fire1981 and I welcome them all as well as those from anyone willing to give an ID here.
Marble--On!!