Gold is funny. You could be standing on a good pay streak, yet move just 3' to either side and never find a speck.
There's no need to be overly cautious - everyone knows where gold has been found in the past, and that there's still more out there to be found. Even giving the county/state you're in and what corner of the county would be of great help.
The rock you pictured is angular, which means it hasn't traveled any distance. So my guess at this point is either from a rock slide, or rock that was mucked out of a mine after blasting. However, the rock also doesn't look overly fractured.
Also, what are you looking to do - placer mine or hard rock? Looking to run old tailings piles? Do you think you're on virgin ground? Help us out a bit, please.