7-30-11>>> Assuming the coin is circulated, the 1887-O Morgan is a common coin, current average values are $37.00-$45.00
Please look at the coin again. No 1887 Morgans exist with CC mintmarks.
There were no silver dollars struck at Carson City in 1887. Any 1887 dollar with a CC mint mark is a counterfeit.
About $27.
42cents
About $150.
"DO" isn't a mint mark. The mint mark on a silver dollar for that year is on the reverse (tails) side, just above the letters "do" in the word "dollar."
One Dollar
Sorry no Carson City mint marks in 1887 on a Morgan dollar. Look at the coin again.
about $25 depending on condition and mint mark
They are still found in circulation, have no silver and are only face value
If the coin has any wear the value is for the silver, about $8.50
The Denver Mint opened in 1906. You may be looking at an O mint mark from the New Orleans Mint which operated until 1909. There's more information at the Related Question.