Crystal Tones® Alchemy Singing Bowls...are made of the highest quality (99.992% pure!) quartz crystal, the finest in gemstones and precious metals such as 24 karat gold, silver and platinum. The process they are created with makes them incredibly resonant, strong, and pure in tone. The tones produced by Crystal Tones® alchemy singing bowls are not just heard by the ear, you feel them in your body, with certain tones affecting your energy for activation, creativity, healing, balancing & meditation.