[Right Wing Assault]

My dad had one that was 9mm. Deemed to big to break up. They had to get it out surgically.

A male relative had one that was 5/8", which is about 16 mm. They broke it up with extracorporeal shock wave lithotripsy. Took several sessions.

[Right Wing Assault]

A lot of people are giving prevention methods, but there are several types of stones and there is no single solution. You may be wasting your time.

From Mayo Clinic:

Medications can control the amount of minerals and salts in your urine and may be helpful in people who form certain kinds of stones. The type of medication your doctor prescribes will depend on the kind of kidney stones you have. Here are some examples:

Calcium stones. To help prevent calcium stones from forming, your doctor may prescribe a thiazide diuretic or a phosphate-containing preparation.

Uric acid stones. Your doctor may prescribe allopurinol (Zyloprim, Aloprim) to reduce uric acid levels in your blood and urine and a medicine to keep your urine alkaline. In some cases, allopurinol and an alkalizing agent may dissolve the uric acid stones.

Struvite stones. To prevent struvite stones, your doctor may recommend strategies to keep your urine free of bacteria that cause infection. Long-term use of antibiotics in small doses may help achieve this goal. For instance, your doctor may recommend an antibiotic before and for a while after surgery to treat your kidney stones.

Cystine stones. Cystine stones can be difficult to treat. Your doctor may recommend that you drink more fluids so that you produce a lot more urine. If that alone doesn't help, your doctor may also prescribe a medication that decreases the amount of cystine in your urine.