Red-Purple Glass Marble?

[Mewtwo]

Hi,

I was wondering where could I find "red-purple" glass marble? Is it at the places after Izumo? Since I've heard you can get one-color marbles in open fields before you reach Izumo like "red glass marble" and "purple glass marble."

So then, would "red-purple" glass marble be places that exceed Izumo and found in open fields as well? Thanks.