Ali bin Abi Talib (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) forbade me, and I do not say that he forbade you, "from wearing a gold ring, coarse silk (qassi) and bright safflower-yellow, and from reciting (the Qur'an) while in ruku' (bowing)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9121