Brt-211. Wt = 3.05g. Diam = 17.1-17.2mm. Authenticity suspect. Looks like a later copy

Au (%)	Ag (%)	Cu (%)	Zn (%)	Ni (%)	Sn (%)	Bi (%)	Pb (%)	As (%)	Fe (%)
90.98	6.03	2.98	0	0	0	0	0	0	0
91.39	5.77	2.77	0	0	0.07	0	0	0	0

Stevens Collection

Authenticity suspect
Photo from Noble Numismatics, sale 124, lot 4174. Listed as later copy