Watch List notes:

Gerona, Spain, billon dinero, Charles I (1516-56), right-facing bust, mintmark G above shield, NGC AU 58, finest and only example in NGC census. Cal-6. 0.79 gram. Oblong flan with bold central design (bust and shield) highlighted with nice luster, the legends cruder and darker, listed in references as a copper issue but XRF tests indicate 15% silver.

Estimate: $200 - $300