An 1879 "Silver Dollar" is a Morgan dollar.
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.
1879 would make it a "Morgan" dollar.
The 1879 Morgan dollar has a diameter of 38.1mm, thickness is 2.4mm.
Not enough details. New Orleans minted Morgan dollars from 1879 to 1904. Please post a new question with the coin's date.
This link shows a 1879 Morgan Dollar: http://www.coinfacts.com/silver_dollars/morgan_dollars/1879_morgan_dollars/1879_morgan_dollar_obv.jpg
Peace dollars were made from 1921 to 1935. An 1879 silver dollar is called a Morgan dollar after its designer George T. Morgan. There's more information at the Related Question
The mint mark would be located on the reverse of the coin, beneath the center of the wreath. In the case of the 1921 Morgan silver dollar, it wouldn't matter as the coins minted in Philadelphia (no mintmark), Denver ("D") and San Francisco ("S") all have similar values. In the case of the 1879 Morgan silver dollar, the Philadelphia, San Francisco and New Orleans ("O") minted coins have roughly similar values, but those minted in Carson City, Nevada ("CC") are worth markedly more.
The Morgan Dollar depicts a personification of Liberty and not a living person.
The 1879 Morgan dollar is not scarce or rare, assuming it's circulated and has no mintmark, average retail values are $30.00 to $41.00 depending on how much wear the coin has.
The 1879 Morgan dollar is not scarce or rare, assuming it's circulated and has no mintmark, average retail values are $26.00 to $32.00 depending on how much wear the coin has.
It's a coin that was minted at the New Orleans Mint. That facility operated from 1838 to 1861 and then again from 1879 to 1909. To find out the value of a specific coin minted there you'll need to post a new question with its date.