I am very sure that all the stones come from by gallbladder now. My gall bladder is diagnosed via ultra-sound as suffering from biliary sludge, which is slightly different from gallstones. After 18 productive flushes I would assume that I am getting to the older stones deep in the gallbladder. Last time they were all dark green and there were a couple of dark ones this time. You can probably work it out as well as me. From what I have read the predominant factor which influences the colour of the stones are their chemical make up.
My research has also revealed that biliary sludge is a common reaction to spinal injuries. I suffered from a very serious back injury some years ago. Whether it is the injury itself or the pain killers that causes the formation of the sludge is not clear. I was taking 8 morphine doses a day and this drug severely interferes with the emptying of the gallbladder.