Some notes from Wikipedia about this subject:
Singing bowls (also known as Tibetan Singing Bowls, Rin gongs, Himalayan bowls or suzu gongs) are a type of bell, specifically classified as a standing bell. Rather than hanging inverted or attached to a handle, singing bowls sit with the bottom surface resting. The sides and rim of singing bowls vibrate to produce sound characterized by a fundamental frequency (first harmonic) and usually two audible harmonic overtones (second and third harmonic). According to singing bowl researcher Joseph Feinstein, singing bowls were traditionally used in Asia and the tradition of making sound with bronze bowls could go back 3,000 or more years to the Bronze Age.
Singing bowls are used worldwide for MEDITATION, MUSIC; RELAXATION AND PERSONAL WELL-BEING. They are used by a wide range of professionals, including health professionals, school teachers, musicians and spiritual teachers. Singing bowls are used in health care by sound healers, psychotherapists, massage therapists, cancer specialists, stress and meditation specialists. They are used to help treat cancer patients and also for post traumatic stress disorder. They are popular in classrooms to help facilitate group activities and focus students’ attention.
Singing bowls were historically made throughout Asia, especially Nepal, China and Japan. They are closely related to decorative bells made along the silk road from the Near East to Western Asia. Today they are made in Nepal, India, Japan, China and Korea.