Understanding the Types of Kidney Stones There are four main types of kidney stones, and each type is composed of different materials. Calcium stones are the most common type of kidney stone, and they can be either calcium oxalate or calcium phosphate. Uric acid stones are less common, but they can be more painful than calcium stones. Struvite stones are another type of kidney stone, and they are usually caused by infection. Lastly, cystine stones are the least common type of kidney stone, and they occur when there is an inherited disorder that causes too much cystine to be excreted in the urine. Kidney stones can vary in size, and they can be as small as a grain of sand or as large as a pearl. They can cause a lot of pain when they pass through the urinary tract, and they can also cause other problems such as urinary tract infections, kidney damage, and blood in the urine. If you think you might have a kidney stone, it's important to see a doctor for kidney stones removal singapore.