Sunan Ibn Majah, Book 32, Hadith 3754 (In-Book) ⓘ
It was narrated that ‘Uthman bin Mawhab said: “I entered upon Umm Salamah and she brought out for me a hair of the Messenger of Allah, which was dyed with henna and Katam.”
حَدَّثَنَا أَبُو بَكْرٍ، حَدَّثَنَا يُونُسُ بْنُ مُحَمَّدٍ، حَدَّثَنَا سَلاَّمُ بْنُ أَبِي مُطِيعٍ، عَنْ عُثْمَانَ بْنِ مَوْهَبٍ، قَالَ دَخَلْتُ عَلَى أُمِّ سَلَمَةَ . قَالَ فَأَخْرَجَتْ إِلَىَّ شَعَرًا مِنْ شَعَرِ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ مَخْضُوبًا بِالْحِنَّاءِ وَالْكَتَمِ .
also referenced under: Hadith 3623 (Reference) & Volume 4, Book 32, Hadith 3623 (DarusSalam)