Found this in my travels through Muscat.

Hello, found this during my travels through Muscat Oman. The seller just told me it was an old currency here in Muscat, but with the writing on it I would assume from somewhere else. Any info would gladly be appreciated.
On the front: it has a S.F. Mint and R IMP HU BO REG. M THERESIAD G.
On the back: BURG CO TYR 1780 X ARCHID AVST DUX

Thanks
gongoin