Musannaf Ibn Abi Shayba 18:404

Abu Bakr narrated to us, he said: Muhammad bin Bakr narrated to us, from Ibn Jurayj, he said: Abd al-Aziz bin Umar informed me that the commanders of the armies and the people of opinion gathered to Umar bin Abd al-Aziz regarding the fingernail, if it is pulled out, or it falls off, or it turns black. The [compensation for the] fingernail, out of the blood money of the finger, is ten dinars.