Hadith: The Messenger of Allah (may Allah's peace and blessings be upon him) was asked about the lost and picked up item whether it was of gold or silver, whereupon he said: Remember the description of its container and the string with which it is tied. Make a public announcement of it for one year. If nobody comes and claims it, then utilize the money but keep it as a trust with you. If its owner comes back one day seeking it, then return it to him

عن زيد بن خالد الجهني رضي الله عنه : «سئل رسول الله صلى الله عليه وسلم عن لُقَطَة الذهب، أو الوَرِق؟ فقال: اعرف وكِاَءَهَا وعِفَاصَهَا، ثم عَرِّفْهَا سَنَةً، فإن لم تُعرَف فاستنفقها، ولتكن وديعة عندك فإن جاء طالبها يوما من الدهر؛ فأدها إليه. وسأله عن ضالة الإبل؟ فقال: ما لك ولها؟ دَعْهَا فإن معها حِذَاَءَهَا وسِقَاءَهَا، تَرِدُ الماء وتأكل الشجر، حتى يجدها رَبُّهَا. وسأله عن الشاة؟ فقال: خذها؛ فإنما هي لك، أو لأخيك، أو للذئب».
[صحيح] - [متفق عليه]

Zayd ibn Khālid al-Juhani (may Allah be pleased with him) reported that the Messenger of Allah (may Allah's peace and blessings be upon him) was asked about the lost and picked up item that is made of gold or silver, whereupon he said: "Remember the description of its container and the string with which it is tied. Make a public announcement of it for one year. If nobody comes and claims it, then utilize the money but keep it as a trust with you. If its owner comes back one day seeking it, then return it to him." Then, he asked him about the lost camel, whereupon the Prophet (may Allah's peace and blessings be upon him) said: "It is none of your concern. Leave it, for it has its feet and a water container (reservoir), and it will reach water and eat from the trees until its owner finds it." He then asked him about the lost sheep, whereupon he said: "Take it, for it is either for you, or for your brother, or for the wolf."
[Authentic hadith] - [Narrated by Bukhari & Muslim]

Explanation

A man asked the Prophet (may Allah's peace and blessings be upon him) about the ruling on lost property, such as gold, silver, camels, and sheep. The Prophet (may Allah's peace and blessings be upon him) clarified to him the ruling on these things so that it could be an example of other similar lost properties that would, thus, take the same ruling. He said about gold and silver: Remember the description of its container and the string with which it is tied, so that you can distinguish it from your own property and you can tell if it belongs to those who claim it. If one comes claiming it, and his description of such an item matches the description that you know, then give it to that person; otherwise, it will be clear to you that his claim is false. Then, the Prophet (may Allah's peace and blessings be upon him) ordered him to announce it for one year after finding it. The announcement should be made in public places where people gather like the markets, at the doors of mosques, in public assembly places, and in the place where it was found. Then, the Prophet (may Allah's peace and blessings be upon him) allowed him - after announcing it in public for one year and not finding its owner - to spend it or use it. If the owner appears at any time, then the one who found it should give it to him. As for a lost camel and the like, the Prophet (may Allah's peace and blessings be upon him) prohibited him from taking it, because it does not need anyone to protect it. It is naturally an animal that can take care of itself and protect itself from small wild animals. A camel has hooves and legs that can travel long distances; its neck enables it to eat from the trees and drink water, and its stomach is equipped to store water and food. So the camel can protect itself until it is found by its owner who will be looking for it in the place where it got lost. As for lost sheep and other small animals, the Prophet (may Allah's peace and blessings be upon him) ordered him to take it and protect it from destruction or being attacked by predatory animals. After taking possession of it, either its owner will come and claim it, or a year will pass after announcing it with no one to claim it, so it will be a property of the one who found it.