Chakra Tuned Quartz Crystal Singing Bowls are precisely manufactered from the highest purity 99.995% quartz crystal. Each bowl is hand-tuned to a note of the diatonic musical scale. When played, the bowl resonates ("sings") its particular note, opening and balancing the corresponding energy vortex (Chakra) of the body. The note this bowl is tuned to play determines which Chakra is balanced. The size of the bowl determines its tone and octave (the bigger the bowl, the deeper the tone and the lower the octave)