Thank you again @Steph! To let you all know that I'm not totally lazy in my research (lol), here are some of the artists and results that I found, with no conclusive results. Used this list plus other artist my research uncovered:
Jim Cooprider, but he appears to have been an artist mostly in the 1980's?, but no comparable signature that I could find.
Joe Crisanti appears to have a cane like stamp that he uses, not an etched signature, and his style seems very much different than my example.
Jared Csakany -- no examples found
Jason Compagni -- only one real example that I could find, and his signature was his full name, not the "JC" I was looking for
Jerry Capel -- I suppose this artist is a possibility, as he has been known for making marbles, but I cannot find a comparable signature or similar examples.
John Choko -- Did sign pieces "JC", but unfortunately passed away in 1991.
Jean Claude Novaro -- Another slim possibility, he did sign his name "J C Novaro" but his signature style is different, and he seems to specialize in mediums other than marbles.
JC Herrell -- Cannot find an example to compare, especially the signature, appears this artist specializes in glass beads primarily.