The white-frosted Meinl Sonic Energy Crystal Singing Bowls are made of high-purity quartz to create a very pleasant aura with their sound and design. A long-lasting, spherical tone spreads when the singing bowl is gently tapped or rubbed. All Crystal Singing Bowls are delivered with a silicone ring to avoid possible impact and to ensure the best resonance. The corresponding heart chakra promotes confidence, optimism, warmth, cheerfulness, compassion and helpfulness.