THE MINERALOGY AND GEOCHEMISTRY OF SYNTHESIZED CALCIUM OXALATE KIDNEY STONES

Kidney stones are an increasing public health issue that affects approximately 10-20% of the world population. They are microscopic mineral crystals that aggregate in the kidneys, and have the phase compositions of oxalate, phosphate, urate, cystine, or a mixture of several phases. They cause many health problems including blocked urine flow and even renal failure. The most common type of kidney stone is the calcium oxalate mineral, Whewellite (CaC₂O₄^.H₂O), which forms in the kidneys by supersaturation, then aggregates to other crystals by adhesion with renal tubular epithelial cells. Previous research has indicated that the chemistry, temperature, and pH of the urine play a major role in stone formation. We synthesized calcium oxalate and other types of crystals (ex. gypsum) in synthetic urine solutions at various pH conditions, varying salt concentrations, and various organic urinary component (urea and creatinine) concentrations to understand their effects on kidney stone formation. We examined the synthesized crystals with XRD to identify the mineralogy of the crystals and microscopy to identify crystal shapes and growth behavior. Our research has indicated that the organic urinary molecules (creatinine and urea) present play a role in the formation, mineralogy, and morphology of the microcrystals. Understanding the formation of these minerals will aid in the development of treatment and prevention strategies for these debilitating minerals.