"With a satisfied expression, he regraded the field of ripe corns with flowers, draped in a curtain of rain. But suddenly a strong wind began to blow and along with the rain very large hailstones began to fall. These truly did resemble new silver coins. The boys, exposing themselves to the rain, ran out to collect the frozen pearls".
In the above passage, The frozen pearls in the story " A Letter to God" G.L. Fuentes refers to hailstones. The frozen pearls give rise to hope that rain would stop and finally come to end. These large hailstones looks like silver coins.