Oh, cool - an old Danish 4 mark! These had the dual denomination of 1 'krone'. As any Dane would know, coins of this denomination are still in circulation, though they are no longer made of silver, and much smaller nowadays.
Struck under Frederik III of Denmark (note the F3 monogram), these coins were issued for four years; from 1654 until 1657. There are two different varieties. The difference is found in the coat-of-arms: one variety (let's call it A) has three hearts at each side of the lions, and three hearts below them. The other variety (we'll call it B) has four hearts at each side and one heart below. Only in 1655 were both types struck.
VARIETY A (1654 and 1655)
worn: $115 US dollars approximate catalog value
average circulated: $450
well preserved: $800+
VARIETY B (1655, 1656 and 1657)
average circulated: $700
well preserved: $1000+
coins of variety B dated 1656 are so rare that the catalogs do not even show their value.
The coin in our picture is in very nice shape. It sold at 1250 euros (about $1350 US dollars) by Bruun Rasmussen during a 2015 auction. CoinQuest thanks Bruun for use of his coin photo.
These coins are made of 67.1% pure silver, and were issued to a weight standard of 22.272 grams. Most coins will weigh a bit less than this due to circulation. If you have a coin weighing less than 20 grams, and there's not a big chunk missing from it, then it's likely counterfeit.
The values listed on this page are catalog values. Please see our Important Terminology page in order to translate them into actual buy and sell values.