In reply to:
borax requires evaporation to form; thus deposits will only be found in deserts.
Well borax is a salt-- but there are salt deposits to be found in non desert areas, presumably the areas were deserts in the distant past– or they are dried lake beds from salt lakes.
There are salt mines in NY (Watkin's Glen area– well known to auto race fans.) The salt deposits are deep underground, and are mined by pumping down water, extracting the brine, and evaporating the water. Watkin's Glen, even if you have never been there is not a desert or even close to one.
And there are solid salt "quarries" in what is now southern Poland–still not "played out" even though mining has been going on since the Roman's time. I don't think of Poland has large extensive deserts-- though like NY state, it might have some small deserts or desert like areas.
So salt mining is not only done in the desert. I just never had any idea of what borax was used for besides washing. I actually prefer hydrated sodium carbonate to hydrated sodium borate for cleaning. (Washing soda--not Borax) and for really tough jobs, tri-sodium phosphate– but use of tri-sodium is restricted.
