I was reading all of the older posts regarding colloidal silver and did some research as a matter of interest. I found what appears to be a legit site with some very interesting information. http://www.silver-colloids.com/Reports/reports.html?partner=37&gclid=CPmSr4z-7LACFYS6KgodjFi0ug . You can copy and paste it to your browser. It basically says that most of the so-called colloidal silver out there is in fact silver IONS not colloidal and can cause argyria; a TRUE colloidal will not cause argyria!! Also, the real deal is never clear, like water. When exposed to light it will reflect a color.
The really great thing is that it lists some companies that sell the ions and some that sell the real colloidal. I hope that helps, it sure helped me!