Cobalt Blue Cube-Diamond Depression Glass Fostoria?Jeannette?Indiana?

This is a 12'' Round Plate- torte plate?- it is flat with a blue quarter inch stand/foot that goes the entire way around in the center. It has 4 seams throughout, I know that Fostoria has 3 seams and I also recently learnt that fostoria did not or rarely made colored glass, especially cobalt blue. I have searched and searched online, books and etc. trying to find out what this is. Does not look like Whitehall by Indiana, nor does it look like Jeanette Glass' Cube pattern. The only thing I have found that truly could possibly be a match is Fostoria American pattern but I can only find the clear glass, never the cobalt. Only diffrence really is that the lip of this pattern is turned up, they call it a torte plate. Mine is flat. I tried listing it somewhere as Fostoria and had several people tell me it was not... Clueless.