The Monolith Monsters (1957) on Netflix

Government geologist Dave Miller returns to his office in San Angelo to find it wrecked, strewn with black rocks. He also finds his fellow geologist dead, seemingly turned to stone. He can make little sense of it nor can the local doctor diagnose what may have killed his friend. When the Simpson farm is destroyed - also covered with the same black rocks - they find little Ginny Simpson as the only survivor. She too is afflicted with her right hand turned to stone and spreading. When they transfer her to Los Angeles, Dave calls on his former professor, Arthur Flanders, who concludes the rock has to be a meteorite. What they soon learn is that the rocks grow when in contact with water - and the growing rocks are on a path directly to San Angelo. They have only a few hours to find a way to stop them.