It's not a US coin, it's a privately made "silver round" sold for its metal content. You need to know what purity and weight of silver is in it. On most rounds that information is displayed somewhere within the design; e.g. "1 oz .999 Fine" or similar.
If it doesn't have that information it's probably not real silver, or only silver plate.
"DO" isn't a mint mark. The mint mark on a silver dollar for that year is on the reverse (tails) side, just above the letters "do" in the word "dollar."
If their is one it's on the back above the letters DO in the word dollar
Likely $18.00-$20.00 just for the silver. the 1880 date is very common, but check the back of the coin for a mintmark, if it has a "CC" mintmark it's worth a lot more.
It's not a US coin, it's a privately made "silver round" sold for its metal content. You need to know what purity and weight of silver is in it. On most rounds that information is displayed somewhere within the design; e.g. "1 oz .999 Fine" or similar.If it doesn't have that information it's probably not real silver, or only silver plate.
Please post new question with more information about the "1" on the reverse. Specifically where is it located and the size.
$27 to $70,000 depending upon the mint mark, the variety and the condition of the coin.
above the DO in dollar on the back :]
M is the monogram of George Morgan, the coin's designer - hence, Morgan dollar ! You need to look on the back for a mint mark. See Related Questions for more specific information.
The mint mark area is located on the back, between the wreath's bow and the letters DO in DOLLAR: blank = Philadelphia D = Denver S = San Francisco O = New Orleans CC = Carson City Here's a picture of a CC dollar:
Values are: No mint mark, "O", or "S" - about $17 "CC" mint mark - $100 if worn, $200+ with only moderate wear. Note that there are Morgan dollars and Trade dollars, but they're different coins. Trade dollars all have those words on the back. Plus, 1880 trade dollars were only issued in proof, so it's almost certain you have a Morgan dollar (the classic silver dollar most people think of)
It's Probably Nothing.
Sorry this isn't a American silver eagle. This is a Morgan silver dollar. The mintmark is located above the DO in DOLLAR on the back of the coin.