It looks Gibson to me. Is it signed? Mr. Gibson didn't sign his marbles. His shop was in Milton, West Virginia and he retired and sold the shop a few years ago. The lead blocker at Blenko bought the shop, name is David and i can't think of the last name. A couple of the Gibson daughters bought an antique store in Milton and set up a shop to sell glass.
I can't tell you how numerous they are. We sold a bunch of them and have some in our collection. Charles Gibson made several styles. The snakeskin is probably the best known. Toward the end, maybe late 90's, he made some with goldstone. They're probably the least numerous. As far as i know he's still living, but we haven't been by to inquire in a long time. Edna