This coin was one I bought in a roll of Mexican 50 Centavos when silver was a bit higher than it is now. There were some uncommon dates in the group, but the 1939 isn’t one of them.
The obverse shows a Phrygian cap radiating beams of light over the denomination (“50 / Centavos”) over the date (“1939”). There’s a wreath clockwise from 2:00 to 7:00 formed by 2 crossed branches of leaves. The branch on the right appears to be olive, and the branch on the left appears to be oak. The cap is labelled “Libertad” (Liberty) and the mint mark (“M”) is between the 5 & the 0.
On the reverse, an eagle stands atop a cactus with it’s breast facing the viewer, it’s wings spread, and a snake in it’s beak. Crenellations run around the inside of the rim, and the legend “Estados Unidos Mexicanos” runs from 6:00 to 3:00 along the inside of the rim. The fineness of the coin “0.7 20” appears on either side of the eagle’s head. A wreath of olive and oak leaves is bound together with a ribbon below the cactus and runs from 4:00 to 8:00.
Identification code: KM-447
Mint Mark: n/a
Mintage: 10,440,000 (a fairly large mintage, but still only 4.2% of the 247,934,000 coins minted of this type in 11 dates of issue from 1919 to 1945
Country of origin: Mexico
Composition: 72% silver, with the remainder likely being copper
Weight: 8.3g (0.1929 oz ASW)
Estimated Value: ~$5 in circulated condition like this with silver at ~$19/oz