About Calculus Of Kidney. Calculus of kidney, also called renal calculus or more commonly known as kidney stones, is a condition in which waste materials from urine in the kidneys forms a solid, hard stone. Calculus of kidney symptoms include severe pain in the back or groin area, along with changes in urine, fever, vomiting, and nausea. Pain may strike quickly, and suddenly disappear. Calculus of kidney most commonly occurs as a result of dehydration.