This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
Renal stones which are laminated and irregular in outline are 
Select and explain. 
A. Uric acid, B. Calcium oxalate, C. Struvite, D. Cystine
B: Calcium oxalate
Answer: B: Calcium oxalate 
Explanation: Calcium oxalate stones are laminated and irregular in shape and covered with sharp projections which cause bleeding. The surface of these stones are thus discoloured by altered blood- brown in colour- mulberry stones Reference : page 1296 Bailey and Love's sho practice of surgery 25th edition