Kidney stones are hard masses of crystallized minerals that form in the kidney after separating from the urine in the urinary tract. Kidney stones are known to be one of the most common, and most painful, disorders of the urinary tract. Kidney stones are most common among Caucasians and affect approximately 12 percent of men and five percent of women by the age of 70. Most people suffering from kidney stones experience them between the ages of 20 and 40 years old. Kidney stones are more common in hot climates, with peak kidney stone incidence rates occurring one to two months after the hottest months of the year. Recurrence rates are approximately 50% within 5 years of an initial kidney stone episode.