It is narrated from Sayyiduna Iyad bin Himar al-Mujashi'i (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever finds a lost item, let him take two upright persons, or one, as witnesses, and let him neither conceal it nor hide it away. If its owner comes, he has the most right to it; otherwise it is the wealth of Allah, which He gives to whomever He wills."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب اللقطة / 12057