Hello, Laura -- It is a little difficult to tell exactly what coin you have, but this is our best guess. It is a gorgeous gold sovereign from the Isle of Man. It is worth its weight in gold.
A few decades ago, like many governments, the Isle of Man figured out that it could make a lot of money minting coins and selling them to investors and collectors. Laura's coin, with the young portrait of Queen Elizabeth and the impressive Viking warrior is especially attractive. There are many, many other patters in gold, silver, and other exotic precious metals.
The coin in our picture comes from APMEX.com a respected seller of precious metals, and CoinQuest thanks APMEX for granting us copyright release.
To figure an approximate value of an Isle of Man Viking coin, use a web site such as kitco.com to determine the current value of gold per troy ounce. Then multiply that value by the number of troy ounces in your coin, as follows:
1/2 SOVEREIGN (18 mm diameter): 0.1174 troy ounces
SOVEREIGN or 1 POUND (22 mm diameter): 0.2347 ounces
2 POUNDS (29 mm diameter): 0.4695 ounces
5 POUNDS (36 mm diameter): 1.1737 ounces
For example, at this writing, the value of gold is about $1230 US dollars per troy ounce. Tomorrow it will be different, so look it up. If you have, for instance, a 2 pound coin, the value would be 1230 x 0.4695 = $577 US dollars.
When gold coins are bought and sold, the buyer or seller adds or subtracts a few percentage points from the gold value to keep the dealership solvent. The actual mark-ups vary with the condition of the coin(s) and the size of the transaction.