One 1977, one 1978. they are both 20 grams pure silver. they say cien pesos, plata pura, 20 g.r. ley 720 another one that says cinco pesos, 30 gramos ley 0.900.m, 1948, estados unidos mexicanos.
I dont believe they are Pure Silver. The two that say 20 grams .720 are most likely 72% silver. The last one that says .900 is prob 90% silver. The Silver coins that the US Minted were 90% silver. So you have two 20 gram coins that contain 72% Silver, then one 30 gram coin that contains 90% silver.
