Q're Crystal singing bowls are made of pure quartz (essentially 99.9% silicon quartz) and sand in a spinning mold, in a process thatheats the mixture to about 4000 degrees.Each quartz singing bowl is digitally matched to the musical scale - C, D, E, F, G, A, B - which relates to different chakras of your body. Bigger bowls produce deeper sounds which have a more grounding effect and resonate more strongly with the physical aspect. Smaller bowls have a higher pitch which stimulates higher chakras and resonates more with the spiritual aspect.