Today any 1879 Morgan silver dollar value is a minimum of $25.25 . Your old coin is heavy with over 3/4 ounce pure silver, forming a high base price.
Now add in the popularity of collecting silver dollars and collector demand, with the result, many are worth far above silver value.
Here are key factors to consider in your coin values.
Mintmarks: Evident by the chart, 1879 dollars with the "CC" mintmark are scarce today because of low production numbers when first minted. A close up image to help locate mintmarks is further down the page.
Condition: Rare coin dealers and collectors avidly search for nice condition coins. Top quality is rare and desirable, however less popular are heavily worn 1879 silver dollars, these trade close to silver value. If your coin still retains its original detail with no wear it is easily a higher value silver dollar.
Discovering rare mintmarks and high condition all contributes to how much your old silver dollar is worth.