The table below summarizes crystals that may be observed in normal urine sediment.
Amorphous urates |  | Dark or yellow-red granules |
Calcium oxalate |  dihydrate  monohydrate | Envelope (dihydrate form) Oval, dumbbell (monohydrate form) Calcium oxalate crystals can be found in both normal and abnormal urine, and that they can be found in a range of urine pH from acidic to neutral. |
Uric acid |  | Various shapes-- rhombus, hexagonal plates, rosettes, rectangles, irregular shapes
Colorless to yellow or brown |
Ammonium biurate |  | Round with thorny projections
Dark yellow to brown |
Amorphous phosphate |  | Amorphous granules |
Calcium phosphate |  | Flat rectangles, prisms, rosettes |
Triple phosphate |  | Four to six-sided prisms resembling coffin lids |
