There were 2 dollar coins minted in 1921, Morgan dollars and Peace dollars, without knowing which coin it was, it is impossible to say what it is worth.
A date an denomination are needed, post new question.
NOTE: An E-PLURIBUS-UNUM coin does NOT EXIST.
Please post new question with the country and denomination of the coin.
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Please look at the coin again. There are no 1921 CC Morgan dollars.
The 1921 Morgan regardless of mintmark is the most common of all Morgan dollars. An circulated coin is $37.00-$44.00
Assuming the coin is circulated retail prices are $17.00-$26.00
Based on Condition, the coin is worth $12.49 - $16.99. If kept longer over time, it may be worth more.
Post a new question and include the denomination, mintmark and condition.
Much more information is needed - please post a new question with the coin's date and the country that minted it. If it's a US coin, look for a small D or S mint mark.
Could you tell us a bit more about this coin? I won't say for certain that no coins designed by Morgan were made in 1929, but the dollar coin that is named for him was not minted after 1921.
The series of US "MERCURY" coins are dimes not dollars, post new question.
In 1921 two types silver dollars were issued and the values are very different. If the coin has the motto E PLURIBUS UNUM above Liberty's Head it's a Morgan dollar and the value is $37.00-$41.00 for a circulated coin. If the coin has the word Liberty above her head it's a Peace dollar and the value for a circulated coin is $80.00-$175.00 Both coins are dated 1921.
The 1921 Morgan is the highest mintage, most common of all Morgan dollars. Retail values are $25.00-$45.00 for a average Mint State coin.