The city of Riga is in modern-day Latvia, across the Baltic Sea from modern-day Sweden. Back in the early 1600s, Riga was part of Livonia, a region of turbulence as Russia, Poland, Lithuania, and Sweden scrambled for rulership. The name on the coin is Gustav Adolph II, King of Sweden, so we classified this coin under Sweden. Sometimes you see it under Livonia or simply 'Baltic States.'
The denomination is 1/24 thaler. It is made of silver. The collector values are not that high even though the coin is quite old.
worn: $10 US dollars approximate catalog value
average circulated: $30
well preserved: $60
You can find worn examples selling on eBay for as low as $2. A nice specimen like the one in our picture would probably bring $25 at auction.