Al-Muwatta Hadith 27.6

Yahya related to me from Malik from Abdu Rabbih ibn Said that Abu Bakr ibn Abd ar-Rahman ibn al-Harith ibn Hisham only gave a fixed share to two grandmothers (together). Malik said, "The generally agreed on way of doing things among us in which there is no dispute and which I saw the people of knowledge in our city doing, is that the maternal grandmother does not inherit anything at all with the mother. Outside of that, she is given a sixth as a fixed share. The paternal grandmotherdoes not inherit anything along with the mother or the father. Outside of that she is given a sixth as a fixed share." If both the paternal grandmother and maternal grandmother are alive, and the deceased does not have a father or mother outside of them, Malik said,."I have heard that if the maternal grandmother is the nearest of the two of them, then she has a sixth instead of the paternal grandmother. If the paternal grandmother is nearer, or they are in the same position in relation to the deceased, the sixth is divided equally between them." Malik said, "None of the female grand-relations except for these two has any inheritance because I have heard that the Messenger of Allah, may Allah bless him and grant him peace, gave the grandmother inheritance, and then Abu Bakr asked about that until someone reliable related from the Messenger of Allah, may Allah bless him and grant him peace, that he had made the grandmother an heir and given a share to her. Another grandmother came to Umar ibn al-Khattab, and he said, 'I am not one to add to fixed shares. If there are two of you together, it is between you. If either of you is left alone with it, it is hers.' " Malik said, "We do not know of anyone who made other than the two grandmothers heirs from the beginning of Islam to this day."