PrettyLitter is made of super absorbent Silica Gel, combined with a proprietary health indicating formula to help you monitor your cat's urine for acidity and alkalinity levels outside the average range, plus the visible presence of blood. Silica Gel litter is made from naturally occurring minerals, so PrettyLitter is safe for your cat and friendly for the whole household. PrettyLitter is manufactured in one of the world's largest and most trusted kitty litter plants sourcing its own silica microgels using carefully selected mineral sources. In addition, our manufacturing facility uses the highest quality control standards.