Stones can form in at least eight different locations in your body, not just the kidneys. Anywhere minerals, salts, or other substances sit long enough in a confined space, they can crystallize into hard deposits. Some are extremely common, like kidney stones and gallstones, while others, like nasal stones, are rare enough that many doctors go their entire careers without seeing one.
Kidneys
Kidney stones are the most well-known type, affecting roughly 9 to 10 percent of U.S. adults. Their prevalence has more than doubled since the late 1970s, when it sat around 3.8 percent. Rates have stabilized in men but continue to rise in women. Obesity and diabetes both increase risk, partly because they raise levels of uric acid, calcium, and oxalate in the urine.
Stones form when dissolved minerals in your urine become concentrated enough to crystallize. This can happen deep inside the kidney’s filtration system, where tiny crystals grow and eventually lodge in the narrow tubules, or on the surface of the inner kidney tissue where mineral plaques build up over time. Most kidney stones are made of calcium oxalate, though uric acid and other compositions exist. You typically won’t feel a kidney stone until it moves out of the kidney and into the ureter, the narrow tube connecting the kidney to the bladder, where it causes the sharp, wave-like flank pain most people associate with “passing a stone.”
Gallbladder
Gallstones form in the gallbladder, a small pouch beneath your liver that stores bile. They come in two main types. Cholesterol gallstones are the more common variety, driven by risk factors like female sex, obesity, rapid weight loss, high-calorie diets, pregnancy, and estrogen-based medications. Pigment gallstones are built primarily from calcium bilirubinate and are more closely linked to conditions that break down red blood cells (chronic hemolytic anemia), liver cirrhosis, and type 2 diabetes.
Many people with gallstones never know it. The trouble starts when a stone blocks the duct that drains the gallbladder, causing sudden pain in the upper right abdomen, often after a fatty meal. That pain typically lasts 30 minutes to several hours and can radiate to the shoulder or back.
Salivary Glands
Your salivary glands can develop calcium-based stones that block the flow of saliva. About 80 percent of salivary stones form in the submandibular gland, the large gland beneath your jaw. Another 10 to 20 percent occur in the parotid gland, near the ear, and a small fraction form in the sublingual gland under the tongue. The submandibular gland is most vulnerable because its duct runs upward against gravity and produces thicker, more mineral-rich saliva.
The classic symptom is a painful swelling under the jaw or in the cheek that flares up during meals, when the gland tries to push saliva past the blockage. The swelling usually fades over two to three hours as saliva slowly seeps around the stone.
Tonsils
Tonsil stones form in the small pockets and folds (crypts) on the surface of your tonsils. Bacteria, dead cells, and food debris collect in these crypts, and over time the material calcifies into small, pale, foul-smelling lumps. The stones are primarily calcium carbonate, along with traces of magnesium, sodium, and other minerals. They’re essentially a living biofilm: bacteria actively colonize the stone, with oxygen-using bacteria on the surface and oxygen-avoiding bacteria embedded deeper inside.
Tonsil stones are usually tiny and harmless, though they’re a common cause of persistent bad breath. You might notice a scratchy feeling in the back of your throat or cough up a small, chalky white fragment. People with deep or heavily folded tonsillar crypts are more prone to them.
Bladder
Bladder stones form when urine stays in the bladder too long, allowing minerals to crystallize. The leading cause is incomplete bladder emptying due to an enlarged prostate, which accounts for 45 to nearly 80 percent of bladder stone cases. Neurogenic bladder, a condition where nerve damage prevents the bladder from emptying properly, is the other major cause. Up to two-thirds of people with spinal cord injuries and neurogenic bladder develop bladder stones, and those with permanent indwelling catheters face six times the risk of someone who urinates normally.
Symptoms include lower abdominal pain, difficulty urinating, a frequent urge to urinate, and sometimes blood in the urine. Unlike kidney stones, bladder stones tend to signal an underlying problem with how the bladder drains rather than a dietary or metabolic issue.
Pancreatic Duct
Stones in the pancreas are a consequence of chronic pancreatitis, a progressive inflammatory condition most often caused by long-term alcohol use or gallstones. As the disease advances, calcium carbonate deposits form in the main pancreatic duct, its branches, or the surrounding tissue. About 90 percent of people with chronic pancreatitis eventually develop these calcifications.
Pancreatic stones cause problems by blocking the duct, which raises pressure inside the organ and leads to persistent, often severe abdominal pain. Interestingly, stones in people whose chronic pancreatitis is not related to alcohol tend to be larger and denser than those found in alcohol-related cases. In alcohol-related pancreatitis, the gland produces less of a protein that normally keeps calcium dissolved, so calcium carbonate crystallizes more readily. Removing the stones, either surgically or through an endoscopic procedure, reliably reduces pain for most patients.
Appendix
Hard, stone-like deposits called appendicoliths can form inside the appendix. In one study of 321 patients found to have appendicoliths on CT imaging, about 32 percent had acute appendicitis while the remaining 68 percent had the stones as incidental findings with no active inflammation. Larger or multiple appendicoliths raise suspicion for appendicitis, particularly in borderline cases where symptoms aren’t clear-cut. Most appendicoliths that aren’t causing problems are simply monitored.
Veins
Phleboliths are small calcified deposits that form inside veins, most commonly in the pelvis. They develop when a tiny blood clot in a vein wall slowly becomes layered with calcium and fibrous tissue. Phleboliths are extremely common and almost always harmless, but they frequently show up on X-rays and CT scans, where they can be mistaken for kidney or ureteral stones. Radiologists distinguish them by their round shape and a characteristic bright center on imaging, compared to the more irregular, denser appearance of urinary stones.
Nasal Cavity
Rhinoliths, or nasal stones, are the rarest stones on this list. They form when a small object or piece of debris gets stuck in the nasal passage and, over months or years, becomes coated with mineral salt deposits from chronic inflammation. The original trigger can be something as mundane as a fruit seed, a piece of gauze, or even an ectopic tooth. A deviated septum may contribute by creating areas of stagnant airflow where debris accumulates, and poor mucus clearance can allow the buildup to continue unchecked. Symptoms mimic chronic sinusitis: one-sided nasal blockage, foul-smelling discharge, and sometimes nosebleeds. Because the symptoms overlap with more common conditions, rhinoliths are often discovered only after imaging or a direct look inside the nose.