Fig. 1.

Human gallbladder stones. Pure cholesterol stones with spherical shape and morular surface (a), oval shape and smooth surface (b), multiple stones (c). The cut surface is shown with a brownish centre and radial disposition of cholesterol monohydrate crystals (d). Pure pigment stones are shown as debris (e). Mixed stones are shown as multifaceted concernments (f). Note that the black pigment surface and the inner centre are made of a small amount of solid cholesterol crystals (arrow) Black horizontal line=1 cm.