gold diamonds and natural geological wealth underwater

[popolarbear]

I am curious to understand or hear about what other members know of local gem and mineral hunting underwater. i myself am mainly a fish freak, and have little interest in geological or mineral studies. but it is interesting even so. i have had some other more serious in the subject tell me stories of finding this stuff. actually i have now herd this from several different people so i think this is going on in Minnesota. in fact i have seen gold samples that were taken and they tested true. diamonds also in certain areas and silver of course.
my interest being that these people would only hint at what the search entails, but i think it should be fairly straight forward. for instance much of Minnesota was at one time volcano's. the feet of which are were in Africa the richest deposits of diamonds in the world are found. in Minnesota this roughly coresponds to the areas that have heavy granite formations, then in these areas sometime you find a kaolinic clay that can contain diamonds. interestingly rumor has it that there are some areas were this clay has been mined ...but it has no use except for the extraction of diamonds... anyways early settlers came to Minnesota to find gold and silver using very primitive and simple equipment, they did find some limited amounts. today most of Minnesota is private or probably state owned as far as minereal rights go, but for someone just to stumble upon say afew ounces of gold or silver I doubt if anyone would notice if it was rescued from waste.....

my question is does anyone know much about the underwater search and find of such things? i am curious if certain types of formations or outcrops tend to yield such finds. etc.(private or public discusion fine)...also curious how many pounds of silver or gold most typical small surface viens produced in our area durring the early years of gold mining in minnesota?