Hazrat Ibn Abbas radiyallahu anhuma reports, "Sayyidina Rasoolullah sallallahu alaihe wasallam was once delivering a sermon. He was wearing a black turban, or an oily strip of cloth. (RU)
English reference (RU): Book 16, Hadith 111 (RU)
Arabic reference (RU): Book 17, Hadith 118 (RU)