Instructions
Make sure you're looking at a genuine minted coin. The Peace dollar, if real, should be 38 millimeters across (about an inch and a half), have a reeded (ridged) outer edge, and weigh .77 troy ounces.
Check the coin's date. Peace silver dollars were minted and released to the public from 1921 to 1928, then re-minted in 1934 and 1935. If your coin is not dated in one of these ranges, it's not a genuine Peace silver dollar.
Verify that the images on the coin are the correct ones. The "head" side of the coin should bear a mold of the head of Lady Liberty (facing left) and the words "Liberty" and "In God We Trust." The "tail" side should have an image of a resting (wings folded) eagle perching on a rock and facing right with the words "United States of America," and "E. Pluribus Unum."
Look for the word "peace" in the correct location on the "tails" side of the coin. It is from this word that the Peace Dollar gets its name, and it should be located beneath the eagle on its rock perch in small, capital letters.