The table below summarizes crystals that may be observed in normal urine sediment.
Dark or yellow-red granules
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.
Various shapes-- rhombus, hexagonal plates, rosettes, rectangles, irregular shapes
Colorless to yellow or brown
Round with thorny projections
Dark yellow to brown
Flat rectangles, prisms, rosettes
Four to six-sided prisms resembling coffin lids