Hello. I suppose i should have said Akro Royal Agate. I use the book Popular American Marbles frequently. They only add agate to the name description twice out of 24 Akro types. The marble below on the right, i had presumed was a Royal. ( perhaps wrongly). The one on the left looks similar , almost like the opaque base ran over it. The patch comes through slightly. Thats where my diagnosis of error came from. But im alright with foreign as in my rookie marble world it is more rare then the other..i frequently see and pass by the right type some yellow or white base and or red,blue translucent patch. Generally ten cents. The left is the only one ive seen.