Radiography of the following renal stones shows opacity, EXCEPT:

Uric acid stones are the only radiolucent stone. Kidney Stones: Composition Radiographic Appearance Disease Association(s) Calcium oxalate and calcium phosphate Radiopaque Parathyroid gland hyperplasia, sarcoidosis Uric acid Radiolucent Gout, leukemia, and lymphoma Struvite (triple stones made of magnesium, phosphate and ammonium) Radiopaque Xanthogranulomatous pyelonephritis Cystine Radiopaque Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 16. Pathology of the Kidney and Bladder. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.