1. ACS advances in chemistry textbook - "From Borax to Boranes" which includes how Borax is mined in the US and WW.
PE - That's the kind of nerdy book I would buy...
Anyway, does it discuss the refining of borax and aspects of grades and purity? I suspect that the difference between Pat's technical grade 20 Mule Team borax and ACS Reagent Grade borax could be something as simple as performing one more recrystallization during the refining. It could be something that simple to clean the borax up to make it a higher grade.
That actually sounds kind of interesting. I like blue-green colors, and if you have to vomit, it might as well be pretty...
Another good quote from your source is this:
"However, boric acid poisoning is considerably rarer than in the past because the substance is no longer used as a disinfectant in nurseries. It is also no longer commonly used in medical preparations. Boric acid is an ingredient in some vaginal suppositories used for yeast infections, although this is NOT a standard treatment."
The part about the treatments of patients with open wounds shows an interesting aspect of boron poisoning. Healthy skin is a very good barrier to borax, but if you have open wounds it is readily absorbed into the body which can lead to poisoning.