I have tried to stay out of this as it seems this discussion has happened several times--perhaps on another website. I am a geologist with a minor in mineralogy. Flint [mineralogically =chert] is a cryptocrystalline [some amorphous silica] quartz family mineral composed mainly of SiO2 [plus traces of impurities that give it color. It can hold a small amount of water in its structure, but is basically impervious to water or oils. Water could conceivably be taken up in small amounts in fractures within the chert/flint--such a piece would not be ideal for use as a "flint". With heat, the small amount of bound water in the material could be released and I suppose keeping flints in water might have been thought to keep them from dessicating. I don't think it necessary for sound flints. Flint/chert occurs in various forms. The classic black nodules from the chalk beds in England are the best known--these nodules are generally clean solid silica with few 'flaws'. Bedded cherts are common world-wide and the midcontinent cherts of the USA are one source--I believe Rich Pierce uses them. These cherts are generally stratified rather than separate nodules [though nodular beds exist], extensive and in places interbedded with other rock types. These cherts beds are best called 'rocks' than minerals. They often contain more 'impurities', more fractures, and sometimes micropores. The crystallinity varies more so than the best English flints. Nonetheless they can supply fine material for flints [and were extensively used by natives for tools and points]. The Arkansas Novaculite is a form of bedded chert as is the Boone chert of southern Missouri....I personally don't soak flints.
