>>1074809If you can find good word on common gem-bearing strata, you can look for outcrops of the stuff going by USGS and state or university geologic society maps for your area. They're almost always color coded and will have keys showing the named strata and contacts marked out. River facies will be your best bet, but road cuts and air gaps would work great, too. If you're in the southwest, you can sometimes find stuff in pediments (like little deltas) were stuff would wash down from hills and valleys.
