I found this marble while meatl at old house where found stuff from the late 1700s to the 1950s. I found lots of marbles over the years, but never one that's this dark blue. It has some swirls like a lot of other marbles, is probable something common 1940s or 50s.
I agree. It is a WV swirl. Not sure which manufacturer as it has little to go on as far as identification characteristics. Likely Ravenswood, 1940s or so.