Ah excellent to know! Thank you Gavin and Paul. The decoration on this omsa page (http://www.omsa.org/view-image/?imageid=4893&catid=590) threw me a bit, as the stone looks enamelled.
Is there any chance I could email you a picture of the medallion I'm working on Gavin? I am leaning towards reproduction but would appreciate your thoughts.
Please let me know!