Muhammad bin Ziyad (may Allah have mercy on him) said: I saw a man asking Sayyiduna Abu Umamah (may Allah be pleased with him): What is your view, is ornamenting swords part of kanz (hoarded treasure) or not? Sayyiduna Abu Umamah (may Allah be pleased with him) said: Yes. Then he said: I only tell you what I have heard.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7580