Don't forget that the same sorts of stones are flushed even if you don't take Epsom Salts . My first cleanses were done with olive oil and lemon juice. Next I did olive oil and grapefruit juice but no Epsom Salts . Last few times I have taken e.salts. All flushes produced the same results. There are other messages on this forum of other oils being used (eg. Almond oil). So I think that discredits the solid precipate idea. There are also people who have had their stones analysed at labs and confirmed to be cholesterol. I am still trying to persuade my doctor to find a lab who is prepared to analyse them properly - apparently you need special chemicals to analyse chemicals.
Re: experiment idea: Dogs have Gallstones I think so how about trying your test on poor doggy!!