It is mentioned in traditional reports that Umme Salim came to
meet Holy Prophet (s.a.w.a.) and inquired from him the signs of
rightful divine Caliphate.
His Eminence took some pebbles and softened them in his
hands. Then with the intention of the Prophet it turned into a red
ruby. His Eminence placed his seal on it and its effect left an imprint
on the stone.
Then he said: Whoever does like me is my successor.
After the Prophet, she came to Ameerul Momineen (a.s.) and then to
Imam Hasan (a.s.), Imam Husain (a.s.) and Imam Sajjad (a.s.) one
after another and the Imams also, like the Holy Prophet (s.a.w.a.) placed their seals on the stone.
Behaarul Anwaar, vol. 25, p. 186
Isbaatul Wilayah (Part One) – Ayatullah AliNamazi Shahroodi (r.a.)