Aragon is a large region of Northeast Spain. If you squint, cross your eyes, and (more importantly) know what you are looking for, you can make out ARA on the right side of the king's portrait and GON on the left. Our many thanks to THCoins at World of Coins who identified this piece for us.
The king himself is James I (with several spellings including Jaime, Chaime, Jacme, and Jaume), who reigned in Aragon from 1213 to 1276AD.
There are two denominations with essentially the same pattern:
OBOLO: about one-half gram
DINERO: about one gram
The obolo is somewhat more rare than the dinero:
worn: $30 US dollars approximate catalog value
average circulated: $60
well preserved: $150
worn: $10 US dollars approximate catalog value
average circulated: $30
well preserved: $90
The dinero in our photo is in well preserved condition. It would sell for about $80 US dollars to a collector and about $40 to a coin dealer. If it were an obolo, the values would double.