[EDIT image] Gallstone images...Re: For Those Thinking Of Gallbladder Surgery - Caution-Graphic!

http://images.google.com/imgres?imgurl=http://www.cst.cmich.edu/USERS/DIETR1R...


This is a web page done by a med student at Central Michigan University.

Of note: "Approximately 80 per cent of Gallstones are cholesterol gallstones, which consist chiefly of cholesterol plus bile salts (e.g., taurocholate and glycocholate); the remaining 20 per cent are usually referred to as pigment gallstones, which consist chiefly of bilirubin (the pigment) and calcium salts such as calcium carbonate. (Agnes, 2002). But, composite (= mixed) stones -- i.e., those consisting of a mixture of cholesterol, bilirubin and calcium -- have also been recorded and illustrated -- see Klatt (1998)."

and

"S.G. differs with composition -- cholesterol stones - 0.98-1.07 (so, some of these float on water!); calcareous 2.70+.05
Light transmission - translucent to opaque
Luster - dull to pearly to subvitreous
Breakage - irregular, tend to crumble with only slight impacts
Miscellaneous - Some Gallstones are quite obviously concretionary (Figure C, c) whereas others do not have that appearance even though they must have had similar histories of growth. One group of 98 human gallstones, which I once examined, were brown with irregularly shaped, nearly black zones; ranged from ~ 2 mm to 1 cm in greatest dimension; and were roughly tetrahedral, with the smaller ones quite angular and exhibiting planar faces whereas the larger ones, though exhibiting faces, had rounded edges and corners (see Figure C, a & b). Others, only fragments of which I have seen, included several with diverse green hues (Figure A)."