Musannaf Ibn Abi Shayba 18:398

Abu Bakr narrated to us, he said: Abd al-Rahim ibn Sulayman narrated to us, from Ash'ath ibn Siwar, from Abdullah ibn Dhakwan, from Ibn Abbas: He judged regarding a man's fingernail that a man had injured, causing it to become blind [i.e., causing the loss of the nail or the finger's function], that there is one-tenth of the blood money of the finger [as compensation].