There are four main types of stones:

1. Calcium oxalate: The most common type of kidney stone which is created when calcium combines with oxalate in the urine. Inadequate calcium and fluid intake, as well other conditions, may contribute to their formation.
2. Uric acid: This is another common type of kidney stone. Foods such as organ meats and shellfish have high concentrations of a natural chemical compound known as purines. High purine intake leads to a higher production of monosodium urate, which, under the right conditions, may form stones in the kidneys. The formation of these types of stones tends to run in families.
3. Struvite: These stones are less common and are caused by infections in the upper urinary tract.
4. Cystine: These stones are rare and tend to run in families.