Watch List notes:

TURKEY: Mahmud II, 1808-1839, AV rubiye (0.80g), Kostantiniye, AH1223 year 5, KM-605, AU. The rubiye ("quarter") is ¼ of the sultani (findik), which was struck to the standard of about 3.50g until reduced to 3.20g under Mustafa IV. Thus this rubiye is exactly ¼ of the reduced sultani. It is not ¼ of the zeri mahbub, which weighed about 2.60g, even though this classification has been almost universal in the KM and other catalogs. The rubiye may also be called ¼ sultani, ¼ findik, or ¼ eshrefi (three more different terms for the same denomination).

Estimate: 60-90 USD