Ibn Shihab al-Zuhri (may Allah have mercy on him) says: I read in the letter which the Prophet (peace and blessings be upon him) wrote for Amr bin Hazm (may Allah be pleased with him): "The blood money for one ear is 50 camels."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الديات / 16220