This coin is in great shape, with very little wear on the high points. I would grade it EF40-EF45.
The reverse design features an eagle perched on a shield with symbols from the American flag. At the upper rim are the words “United States of America” and at the bottom is the year of issue. To the left of the year is the mint mark (“S” for San Francisco). Coin with no mint marks were minted at the Philadelphia Mint.
On the obverse, Liberty is shown pounding on the forge of freedom. This image was designed by Melecio Figueroa and there is some speculation that the young Filipina woman shown on the coin was based on his daughter. She is wearing a flowing dress, similar to the garb of Liberty on other period coinage. The obverse of the coin shows Liberty in the act of striking an anvil with a hammer while her other hand holds an olive branch. In the background is Mt. Mayon, an active volcano with smoke billowing from the crater. On the upper edge of the coin is the denomination “Twenty Centavos” and on the lower perimeter is the word “Filipinas”.
Identification code: Philippines KM-166 (minted 1903 to 1906)
Mint Mark: n/a (Philadelphia, Pennsylvania)
Country of origin: United States of America
Composition: 90% silver, 10% copper
Size: 22 mm
Weight: 5.3849g (0.1558 oz ASW)
Other details: This coin has a tiny prick on the reverse that my be a die crack. It stands out under magnification, but not at a casual glance.
Estimated Value: $6-20 (with silver at $31 / ounce)