What this coin looks like (obverse, reverse, mint mark location, special features, etc.): One major variety of the 1861 Liberty Head Gold $2.50 Gold Quarter Eagle features the Type 2 New Reverse.
The old reverse features larger and thicker letters along with more spacing between the letters and rim of the coin. The new reverse features smaller letters with more spacing between the letters - yet less spacing between the letters and rim of the coin.
There are also differences in the designs of the arrows as well. The old reverse features the arrowheads spaced more closely together. The back of the arrow (fletch) is also nearly touching the eagle's claw. The new reverse features much more spacing between the arrowheads and there is also greater spacing between the back of the arrow and the eagle claw. The difference between the Old Reverse vs New Reverse (Type 1 vs Type 2) is depicted below in the example comparison image:
Coin value chart: Typical coin prices, values and worth in USD based on grade/condition