Look on the back of the coin above the DO in DOLLAR to see if there's a small mint mark letter. There may be an O, S, or blank.
1897 is not a rare date for most grades and mint marks. Numismedia lists the following approximate retail values as of 05/2009:
No mint mark:
Very worn condition - $16
Moderately worn - $18
Slightly worn - $20
Almost no wear - $23
A nice uncirculated one might sell for $35 or more.
S mint mark:
Very worn condition - $17
Moderately worn - $20
Slightly worn - $22
Almost no wear - $30
Uncirculated - $55+
O mint mark:
Very worn condition - $17
Moderately worn - $18
Slightly worn - $30
Almost no wear - $150
Uncirculated - $600+
Nearly ALL U.S. coins bear the motto "E Pluribus Unum" ("From many, one") so this is not a distinguishing characteristic of a coin. The denomination, date, mint mark, and condition are the most helpful characteristics to start with.