I read this in a collection of sci-fi short stories when I was in elementary school, so circa mid-to-late 1980s. It might have been published by Scholastic. It's a very short story.
It may have been set on Mars; the planet is low gravity. Sometime in the future, this planet, it could be the Moon or Mars, has been colonized.
A boy who's been out by himself playing baseball; 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. 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.)