We report a rare case of newberyite (magnesium monohydrate phosphate trihydrate) urolithiasis in a young female with a past medical history significant for longstanding autoimmune hepatitis. She presented to the emergency department with newly diagnosed nephrolithiasis. Over the next 2 years, she had recurrent renal calculi and 3 urologic procedures. Notably, she did not have any history of urinary tract infections or genitourinary abnormalities. Her last stone analysis revealed the unusual combination of newberyite and ammonium acid urate. The pathophysiology of ammonium acid urate and newberyite stone formation as well as risk factors of development are discussed in this report.