Diameter - 21.6 mm
Weight - 8.25 gm
More information is needed to make an accurate valuation. If the coin is about the size of a quarter and has either a picture of Sacagawea or a US president on the front, it's a modern $1 coin made of brass, not gold, and is worth exactly one dollar. Feel free to spend it - billions have been made.
Not gold, but gold-plated. Among other things, from 1933 to the 1970s it was illegal to own gold, and in any case a gold coin the size of a half dollar would have been worth loads more than 50 cents. The good news is that while the coin only has a few cents worth of gold plating, the underlying silver coin is worth about 1/3 of the going price for silver metal - as of 04/2011, over $10.
The only gold coin that I am aware of that was minted by the US Treasury in 1924 was the Saint-Gaudens $20 Double Eagle. This coin had a diameter of 34mm and weighed 516 grains (33,436 grams).Its value in extra-fine condition is: $1225.00.
No such coin exists for a few reasons. Number 1, all US coin denominations (that were intended for circulation) greater than $1 are in gold. A silver $20 coin would be huge, the size of 20 silver dollars. (On the other hand, a $20 gold piece is roughly the size of a silver dollar) Number 2, there is no US coin struck with the date of 1776. Nor is there any other country using the currency of "dollar" that would have struck a $20 silver coin. What you have is a fantasy piece, post a new question including what the coin really is, its weight, diameter, and all other information about it, because it is not a US coin. (and most likely isn't even silver)
No such coin (that is intended for circulation) exists. The last silver dollar coin was minted in 1935. The only other coin since then to use the silver dollar size was the Eisenhower dollar first minted in 1971.
The last Morgan Dollars were minted in 1921, the only dollar coin minted in the US in 1980 is the Susan B. Anthony dollar which is about the size of a quarter, not the larger size of a Morgan Dollar coin. They are rather common and only worth one dollar.
It depends on the size of the coin!
Dollar coins are larger in size and amount.
is it the biggest
More information is needed to make an accurate valuation. If the coin is about the size of a quarter and has either a picture of Sacagawea or a US president on the front, it's a modern $1 coin made of brass, not gold, and is worth exactly one dollar. Feel free to spend it - billions have been made.
She is on a dollar coin that is similar in size to a quarter.
Not gold, but gold-plated. Among other things, from 1933 to the 1970s it was illegal to own gold, and in any case a gold coin the size of a half dollar would have been worth loads more than 50 cents. The good news is that while the coin only has a few cents worth of gold plating, the underlying silver coin is worth about 1/3 of the going price for silver metal - as of 04/2011, over $10.
If it's a modern $1 coin (1987 or later) and the same size as a US $1 coin, it's a common circulation piece worth only face value. It's made of brass-plated nickel, not gold.
Largest size or largest denomination? The largest denomination in common use would be the Japanese 500 Yen coin (~$5 US/Canadian) The largest denomination that is theoretically legal tender would be the 1 Million dollar face value 100 Kilogram gold Canadian coin, although its intrinsic value of the gold is worth much more than the 1 million dollar face value! As for the largest size, in common circulation I'd say it would be something roughly the size of the US Eisenhower dollar which still occasionally circulates.
The only gold coin that I am aware of that was minted by the US Treasury in 1924 was the Saint-Gaudens $20 Double Eagle. This coin had a diameter of 34mm and weighed 516 grains (33,436 grams).Its value in extra-fine condition is: $1225.00.
No such coin (that is intended for circulation) exists. The last silver dollar coin was minted in 1935. The only other coin since then to use the silver dollar size was the Eisenhower dollar first minted in 1971.
The 5 cent coin is smaller in diameter than the Two Dollar coin. The Australian 5 cent coin is 19.41 mm in diameter. The Australian Two Dollar coin is 20.62 mm in diameter.