Yo, Crusher -- It sounds like you have an old rigsbankdaler from Denmark. These are valuable coins, especially in good condition. Since you specify your coin as 'worn' it does not look as good as the one in our picture, which comes from Kapaan and Mades in Marl, Germany.
CoinQuest thanks Kapaan and Mades for use of their coin photo. It's a beauty! They are selling their rigsbankdaler for 375 euros (about $490 US dollars) which is a good price for such a nice coin.
The design on these coins changes somewhat over the years. King Frederik VI is on the front of all coins, but the inscritions vary slightly, as does the back of the coin. This page applies to all rigsbankdalers from 1813 to 1839.
Here are some approximate catalog values for these coins. Use our Important Terminology page to convert these catalog values to actual buy and sell values.
worn: $50 US dollars approximate catalog value
average circulated: $200
well preserved (like our picture): $500
Coins dated 1813 with initials IC are the most common. Divide the values above in half for that date. The scarce dates are 1834 and 1835 with initials FF, and 1835 with initials WS. For those scarce coins, multiply the values by 1.5.
Crusher mentions some unusual shapes on his coin. These sound like a deformity added after the minting process. If so, they detract from the value of the coin. Collectors like their coins free of defects.