Kidney stones are usually caused by calcium. 80% of kidney stones are calcium oxalate. Can you stones can also be caused by an accumulation of uric acid. Other forms of kidney stones can be inherited such as cystine stones. Urinary stones are formed in people when they are dehydrated. It can also be due to a lack of citrate in the diet. Citrate can be added back into the diet by taking more citrus fruit like lemon and orange juice.