Calcium oxalate crystals are the most common cause of kidney stones — hard clumps of minerals and other substances that form in the kidneys. These crystals are made from oxalate — a substance found in ...

Urine crystals form when there are too many minerals in a person’s urine. Crystals in urine may cause no symptoms or may include lower back pain and nausea. When there is an excessive buildup of one ...

Urine contains a large number of different chemicals. Under some circumstances, these chemicals may solidify into salt crystals. This is called crystalluria. Crystals can be found in the urine of ...