The presence of crystals in the urine signifies that the body is getting rid of certain waste chemicals, states the American Association for Clinical Chemistry. Having crystals in the urine can be either normal or abnormal depending on the substance that makes up the crystals.
For dissolved substances, or solutes, to form crystals in the urine, three conditions must be present: The urine must be very acidic or very basic; there must be a high concentration of the dissolved substance in the urine, and the temperature of the urine must be high, explains the American Association for Clinical Chemistry.
Types of normal crystals in the urine include amorphous urates, crystalline uric acid, calcium oxalates, amorphous phosphates and calcium carbonate. These substances are found in the urine of healthy individuals, reports the American Association for Clinical Chemistry.
Some solutes that are not normally present in the urine and can form crystals are cystine, tyrosine and leucine, according to the American Association for Clinical Chemistry. Crystals of this type indicate an abnormal metabolic process.
In some cases, crystals in the urine can lead to bladder stones, explains MedlinePlus. Bladder stones are hard buildups of material that form in the bladder. However, they are usually caused by urinary system problems, such as an enlarged prostate or a urinary tract infection.