According to CoinStudy, an 1891 Morgan silver dollar is worth between $27.19 and $293, as of 2014. The value of an individual coin is dependent on its condition and its mint mark.
The mint mark records where a coin was produced. The most valuable 1891 Morgan silver dollars have a Carson City Mint mark, followed by New Orleans, San Francisco and Philadelphia.
The base price of a Morgan silver dollar is determined by the current price of silver per ounce based on the coin's 90 percent silver content weighing .77 troy ounces. Many coin collectors grade coins on a scale of good, fine, extremely fine and uncirculated, with uncirculated coins worth the most.