This is a tough one. I am confident it is an Akro or a Master though. At this point, I could go either way, but I am actually leaning Master now. Maybe I'm just not used to seeing Master's with a black patch?
There is a resemblance, for sure.
Gladys, Is the base glass for these two marbles transparent? Does it look like the color is primarily on the surface of the marbles? If so, I would go with Vitro, and it would be a very nice one, for sure.
It's a very common trait for Vitro, much less common on others, and I've seen it on lots of them from almost all time periods. The seams are often not directly opposite one another either.