Musannaf Ibn Abi Shayba 18:396

Abu Bakr narrated to us, he said: Abd al-Rahim ibn Sulayman narrated to us, from Hajjaj, from Makhul, from Zayd ibn Thabit: That he gave a judgment regarding the fingernail, if it falls off and does not grow back, or grows back changed, [the compensation is] ten dinars. And if it grows back white, then in it is five dinars.