Muwatta Malik, 587

Malik said, "The position which we are agreed upon, and which I have heard the people of knowledge mentioning, is that rikaz refers to treasure which has been found which was buried during the jahiliyya, as long as neither capital is required, nor expense, great labour or inconvenience incurred in recovering it. If capital is required or great labour is incurred, or on one occasion the mark is hit and on another it is missed, then it is not rikaz." Yahya related to me from Malik from Abd ar-Rahman ibn al-Qasim from his father that A'isha, the wife of the Prophet, may Allah bless him and grant him peace, used to look after the orphaned daughters of her brother in her house. They had jewellery (which they wore) and she did not take zakat from this jewellery of theirs

Abdel-rahman Ibn Al-Kassem a rapporté d'après son père que Aicha, la femme du Prophète (salallahou alayhi wa salam) r Sur lui la grâce et la paix d'Allah s'occupait de ses nièces orphelines, qui vivaient sous sa tutelle, leur gardant leurs bijoux, sans qu'elle paie, à leur sujet, la zakat