Abu Ja’far Ibne Jarir Tabari has narrated through his authorities from Mansur that he said: Once when there was a terrible drought, people gathered for the prayer for rain. Meanwhile Imam Hasan (a) arrived there and said:
“People, would you like rain or snow; or you want a rain of pearls?”
They replied: We would welcome whatever you choose.
He said: All three kinds of rain would fall, but you must not pick up the pearls. So he supplicated and first there was rain and then snowfall and finally pearls rained.
On that occasion we saw that he had stretched out his hands and he was plucking stars from the heavens and when he left them they flew up like bird and returned to their places.
Dalailul Imamah, Pg. 64; Ithbatul Huda, Vol. 2, Pg. 561.