Rennie,
You are about 80 miles south and a little east of Llano, so it maybe possible that there maybe some gold in your area, if there is it is most likely fine gold, the only way to find out is to sample all along the creek/stream, look for any bedrock on the banks that is running down into the water/creekbed, in these areas dig out any material that you can find stuck in the cracks and crevices of the bedrock in and out of the water, the gold if any will be down in the bottom of the cracks, use a crowbar and break open the cracks to get as much material out of the cracks as you can, a thin flat tip screwdriver, a piece of wire with the end bent at 90 degree, a turkey baster to suck out material, a stiff brush, etc., anything that you can think of to get the material out will aid you in your quest to see if there is any gold there.
For fine gold it is best if you classify the material into different sizes before panning, you can start with 1/4" hardware cloth, and then windows screen, and then a flour sifter(make sure you use your wife's or sister's old flour sifter and not her new one!!), after classifying, pan the different sizes separately, any gold when panned properly will be one of the last things in your pan, if you do find gold start using a safety pan and pan the material at least 2 to 3 times to get all the fine gold.
Good luck and let us know if you find any gold!!
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