Here at Cat Crystals, we provide 100% tested crystals with their effects measured and efficacy quantified, by measuring their effect on our spiritual companions, cats. Each crystal we sell has been worn by our feline friends, while we have monitored their physical and mental health. The effects are often astonishing, with improved physical and behavioral characteristics; however, most tested crystals show no positive effects at all. Through our testing, these "dud" crystals are screened out and discarded, leaving you with a 100% crystal guarantee that the your purchase will provide the measured benefit thanks to its inherent physical and spiritual healing properties.