Sayyiduna Abu Hurayrah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "In rikaz there is khums." It was said: What is rikaz, O Messenger of Allah? He (peace and blessings be upon him) said: "The silver and gold which Allah Almighty created in the earth on the day the earth was created." [Munkar (denounced); it has preceded before this.]
Only Abdullah bin Sa'id al-Maqburi narrated it, and he is very da'if (weak); Ahmad bin Hanbal, Yahya bin Ma'in and a group of the imams of hadith criticised him.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7640