Salaam and Greetings of Peace:
Muhammad, the Prophet of God (pbuh) was said to have possessed an exceptionally beautiful countenance, and this is certainly inherent in the nobility of his impeccable honesty and intelligence, as well as the adab, the courtesy and manners of his actions and speech in everyday life. His features have been described by several of the companions, such as Ali ibn Abi Talib, his cousin and son-in-law, with whom he was brought up and who knew him intimately. Ali describes the Prophet (pbuh) in these words:
He was neither tall and lanky nor short and stocky, but of medium height. His hair was neither curled nor straight, but moderately wavy. He was not overweight and his face was not plump. He had a round face. His complexion was white, tinged with reddishness. He had big black eyes with long lashes. His bones were heavy and his shoulders broad. He had soft skin, with fine hair covering the line from mid-chest to navel. The palms of his hands and the soles of his feet were firmly padded. He walked with a firm gait, as if striding downhill. On his back between his shoulders lay the Seal of Prophethood, for he was the last of the prophets.
He was the most generous of men in feeling, the most truthful in speech, the gentlest in disposition, and the noblest in lineage. At first encounter, people were awestruck by him, but on closer acquaintance they would come to love him. One who sought to describe him could only say, “Neither before him nor after him did I ever see the like of him.”
From Islamic Spirituality, edited by Seyyed Hossein Nasr