This question comes up fairly often and is a common misunderstanding. US $1 coins made up till 1935 aren't called "eagles" and they don't contain 1 oz of silver. They were ordinary circulation coins made for use in daily commerce. While they do contain silver, it's not as much - about 3/4 of a troy ounce.
"Silver eagles" are modern (1986 and later) coins sold by the Mint as investment pieces, not for spending; their value is linked to the current price of silver and the "$1" value is purely artificial.
The coin you have is frequently called a Morgan dollar after its designer. Its value when minted was in fact exactly $1 because silver was much cheaper and its price was controlled. Today it has value not only for its silver content but for its interest to collectors. There's more information at the Related Question.
This question comes up fairly often and is a common misunderstanding. "Silver eagles" are modern bullion pieces minted beginning in 1986 and sold to collectors as investment pieces.
The largest silver coin issued in 1918 was a half-dollar and it was intended for ordinary spending, not as an investment piece. Please check the back of the coin to see if it says HALF DOLLAR; if so, there's more information at the Related Question.
Please post a new question with the coin's date and mint mark.
Saying that a dollar coin has an eagle on the back isn't specific enough to ID it. An eagle appears on the back of all silver dollars issued from 1794 to 1935, all copper-nickel nickel dollars issued from 1971 to 1999, and all Sacagawea dollars from 2000 to 2008.
4-13-11>> Assuming the coin is circulated and has no mintmarks, retail value is $33.00-$40.00 depending on how much wear the coin shows. The 1888 Morgan is very common.
NOTE: A 1888 silver dollar (Morgan) is NOT known as an eagle. In numismatic terms an "Eagle" is a $10.00 gold coin. The modern one dollar silver bullion coins are "Silver Eagles".
Silver eagles are bullion coins. The value follows the spot price of silver which goes up and down every day. So there is no set price. It may change by a few cents or a couple dollars over night. Current spot price of silver is $21.25 per ounce. A rule of thumb is selling price is spot + $5.00.
The 2012 American Silver Eagles coins are one ounce of pure silver.
Modern Silver Eagles (1986 to date) contain One Ounce of pure silver.
They weigh one troy ounce.
Sorry no US 1845 silver eagles, but there are Seated Liberty dollars of 1845.
1 troy ounce. They are known as silver eagles and have the bullion value on the back.
Yes, Silver Eagles are 99.9% silver.
The first year for Silver Eagles is 1986 and the US never struck any rectangular coins, it's likely a silver ingot bar.
The modern Silver Eagle bullion coin weighs 1 ounce.
What is the price of a silver eagle now today