Sahih al-Bukhari 4864

It is related that Umm 'Atiyya said, "We were forbidden to mourn someone for more than three days except for a husband, who is mourned for four months and ten days. We should not use kohl or perfume nor wear dyed clothes, except for 'asb garments**. We were allowed in purification when one of us had performed a ghusl after menstruation to use a bit of kust azfar. We were forbidden to follow funeral processions." [*Qust or kust is costus, an aromatic food used for fumigation. It is also medicinal. Kust azfar is the same. ** A type of cloth from Yemen in which the yarn is tied together and dyed before being woven so that part of the final fabric remains white and undyed.] XLVII. A woman in mourning wearing 'asb garments