Some years ago I found a big nugget of a whitish metal.it wasn't as heavy as lead.it weighted more like silver but when I heated it with a small propane torch it melted right away so it wasn't silver since it melts at higher temperature.I wonder if it was gallium.
One story I heard about the Sacramento valley was that there was a layer of gold 6 foot deep at the bottom of it....When you think about all the rivers that flow thought it and the amount of gold that has been recovered from them it may not be a story...Art