Gallstone analysis in laboratory?

A few months ago, I did numerous liver/gallbladder flushes using olive oil and lemon juice. The flushes netted about 150 to 175 stones, most about pea sized but a couple as big as a quarter (and thick too!). Visually, they were all moss green color, and looked just like the stones I see on this site and other similar sites. Since I didn't have insurance at the time, I froze them to make sure I could show them to a doctor.

Upon showing them to my doctor (now that I'm insured), she laughed and told me that it was impossible to flush out stones that big. She said that they are feces, even though the color nor the texture seems to suggest so. What I want to do is to prove her wrong. Does anyone know how I would go about finding a lab to analyze one of the stones? I don't want to go through my doctor, who probably already thinks I'm crazy.

Thanks,
agchandler