from Wikipedia
Have you, or a loved one, ever had a kidney stone?
You're not sure? Well then the answer is "no," because these little crystals feel like razor blades and the pain they cause is excruciating so you'd know if anyone you knew had had one.
Data says that one in 10 of us will eventually have kidney stones (or more than one case of it), and that about 500,000 Americans wind up in ERs each year.
The three most common causes of kidney stones (medical name: nephrolithiasis) are calcium oxalate, calcium phosphate, and uric acid (which is also the cause of gout). They can be hereditary, and can be prevented from recurrence with diet and/or drugs).
Below you can check out a very consumer-friendly video from the American Chemical Society about how to avoid kidney stones.