The Book of Divorce
Ṣaḥīḥ Muslim 3740
لاَ تُحِدُّ امْرَأَةٌ عَلَى مَيِّتٍ فَوْقَ ثَلاَثٍ إِلاَّ عَلَى زَوْجٍ أَرْبَعَةَ أَشْهُرٍ وَعَشْرًا وَلاَ تَلْبَسُ ثَوْبًا مَصْبُوغًا إِلاَّ ثَوْبَ عَصْبٍ وَلاَ تَكْتَحِلُ وَلاَ تَمَسُّ طِيبًا إِلاَّ إِذَا طَهُرَتْ نُبْذَةً مِنْ قُسْطٍ أَوْ أَظْفَارٍ
lā tuḥiddu āmraʾatun ʿalā mayyitin fawqa thalāthin illā ʿalā zawjin arbaʿaha ashhurin waʿashran walā talbasu thawban maṣbūghan illā thawba ʿaṣbin walā taktaḥilu walā tamassu ṭīban illā idhā ṭahurat nubdhatan min qusṭin aw aẓfārin
Transliteration generated from the Arabic vowel marks
The full narration
Umm `Atiyya (Allah be pleased with her) reported that Allah's Messenger (ﷺ) had said:A woman must not observe mourning for one who had died for more than three (days) except for four months and ten days in the case of her husband. And she must not wear a dyed garment except one of the types made of dyed yarn, or apply collyrium, or touch perfume except a little perfume or incense, when she has been purified after her courses
Source
Ṣaḥīḥ Muslim · 3740