I read this in a collection of sci-fi short stories when I was in elementary school, so circa mid-to-late 80's. It may have been Mars. Sometime in the future, the moon/Mars has been colonized.
It's a very short story and the only part I remember is a boy who's been out by himself playing baseball, the planet is low gravity, and his ball and bat are futuristic and the ball comes back to him. Then, the boy is running home because of a "hail" warning and his mother is possibly shouting at him from the door to run faster because the "hail" could kill him. Later on, after the storm is over, trucks are coming to collect the "hail" on the ground and the mother wonders to herself why the people on Earth found these clear shiny rocks so enticing (I think it's made clearer that they're diamonds, but I'm not sure).
Any help is greatly appreciated!