It may or may not even be agate..Possibly some other composited material. Hope that helps. Lynne

It does indeed look like the recently made large stone pendants coming from China. Could easily be a banded agate. It is a fairly cheap stone, depending on it's color and pattern. Does not look like a composite material, but difficult to tell from the picture.
One of the ways you can tell it is pretty new is from the hole. It looks lke it has no wear. If it was older, the edges would probably be softer, rounded. Not a 100% rule, but it does help with identification.