It's the marble that once was being called the Sistersville Patch, however it's been accepted by most everyone I believe that Sistersville did not make patches and these are Akros along with the other patches dug at Sistersville. They are exact matches. I've seen it called a robin egg patch a lot lately too.
Ravenswood. Sometimes found with blue also alongside the purple. You can see these on Pages 252, 237, 238, 246, 254 and 255 in the Ravenswood section of the West Virginia Swirls book.