The great Tibetan master Gwalwa Karmapa used to say that singing bowls emit the sound of the void, which is the sound of the universe manifesting. Their origins can be traced back to the shamanic Bon religion, which precedes Buddhism in Tibet by centuries. They were traditionally used in temples for healing and meditation practices.
Their composition is an alloy of “the seven planetary metals”: gold, silver, mercury, copper, iron, tin, and antimony.