The white-frosted Meinl Sonic Energy Crystal Singing Bowls are made of high-purity quartz to create a very pleasant aura. A long-lasting, spherical tone spreads when the singing bowl is gently tapped or rubbed making it ideal for yoga and meditation. All Crystal Singing Bowls are delivered with a silicone ring to avoid possible impact and to ensure the best resonance. The corresponding crown chakra promotes understanding, fullness and connection with the divine origin.