What did your doctor say?
What are your kidney stones made of?
They would be mineral based. Usually it means your body is either getting too much of a mineral, or is unable to beak it down.
Medical questions need to be asked to the doctor or a medical community - not lay people. As an EMT I can tell you asking friends, peers, coworkers and such often leads to misdignoses that cause more harm than good and can actually delay helping a serious problem.