Amorphous crystals are by definition crystals with no identifiable characteristic shape. Amorphous crystals observed at an acid pH (less than 6) are amorphous urate crystals. At a pH greater than 7, they are amorphous phosphate crystals. Between pH 6 and pH 7, they become very difficult to distinguish.
The presence of amorphous crystals is generally of little clinical significance. Their formation is caused by a combination of factors, including decreased urine volume combined with changes in urine pH and often the presence of large quantities of uric acid (meat consumption), or calcium (dairy products) in the diet.