4-9-11>> If the coin is circulated and regardless of mintmark, value is $32.00-$35.00 it's the highest mintage most common date of the series.
The amount of pure silver in the 1922 Peace dollar is .77344oz, all US silver one dollar coins from 1840 to 1935 have this much silver in them.
A high relief 1922 Peace dollar is rare, they have values of $80,000.00 or more.
A 1922 dollar with the word "Peace" on the back would be a Peace dollar rather than a Morgan dollar. "Morgan" refers to George T. Morgan, the artist who designed the silver dollars minted from 1878 to 1904 and in 1921. There's more information at the question "What is the value of a 1922 US silver dollar?"
No circulating silver US coins were 100% silver, all are 90% silver and 10 % copper.
Assuming the coin is circulated, the 1922-D Peace dollar is a very common coin with retail values of $16.00-$22.00 depending on the grade of the coin.
All US silver coins before 1964 were 90% silver. Peace dollars weigh 26.7 gm if not worn, so they contain about 24 gm of pure silver.
The 1922 Peace dollar is not scarce or rare, it's the most common date of the series. Assuming it's circulated, average retail values are $32.00 to $37.00 depending on how much wear the coin has.
7-10-11>>> The coin is a 1922 Peace dollar not an E PLURIBUS UNUM coin, this Latin phrase is the National Motto and is on all US coins dated 1922 to date. The 1922 Peace dollar is the most common coin of the series, circulated coins have retail values of $38.00-$41.00.
1922 is such a common date for silver dollars that the value is only for the silver content. With current silver prices, a '22 Peace dollar is worth about $21. To sell one, either take it to a coin dealer, or post it on eBay.
If you mean a real silver dollar, such as a Morgan or peace dollar the thickness is 2.4mm
Better check your dates again. The only U.S. half dollar with a 1922 date is a Grant Memorial Commemorative. In circulated condition, it's worth about $60. If you have the variety with the extra star, then about $450
$12.00 to $20.00 in circulated condition.