The scene depicted on the front of these beautiful coins from medieval Venice include a kneeling Doge (a political figure of the time) receiving a gonfalon (a flag of religious importance) from a holy man (often a disciple of Jesus Christ). The back shows an image of Christ Himself encircled by stars.
The example in our picture is in exceptional condition. It comes from Mynthandel in Uppsala, Sweden, where it is on sale for 900 euros (about $1200 US dollars). This is a good price for such an exceptional coin.
Mynthandel's coin represents the top end of prices for most of these coins. Four things make Mynthandel's coin special: (1) it is genuine; this coin is highly counterfeited, (2) it is made of gold; some coins with the same pattern are made of silver, (3) it is a full ducat; some coins are smaller 1/2 ducats and zecchinos, and (4) it is in superb condition; most coins are more worn and dull.
If you have a coin like this, it is best to consult a knowledgeable collector or dealer for an in-person appraisal. We can give only general -- very general -- guidance on this web site. You must be especially careful about counterfeits.
Typical values for gold coins like this with typical wear and typical eye appeal depend primarily on size:
1/4 zecchino (about 15 mm diameter): $300
1/2 zecchino (about 20 mm diameter): $300
ducat (about 22 mm diameter): $400
zecchino (about 22 mm diameter): $400
2 zecchini (about 25 mm diameter): $1000
6 zecchini (about 40 mm diameter): $4000
These are very, very approximate values. Research your coin with experts. Here are some web sites with additional information: