Hi Everybody!
To help understand the fundamentals of gold panning, let me introduce you to Specific Gravity… What, you didn’t think this was going to be a physics lesson?
Specific Gravity is the ratio of the density of a material to the density of water. A more dense the material, the faster and farther it sinks in water or water soaked muck.
Water has a specific gravity of 1 because… obviously… it has the same density as water. Gold has a specific gravity of 19.6, meaning it is almost 20 time more dense than water. Iron, another common metal found in stream beads, has a specific gravity of around 7.5 meaning that gold is about 2 and a half times more dense than iron.
Now, compare those to broken granite, gravel, and quartz with a specific gravities between 1.5 and 1.7, and you can see why looking for gold using water is so popular. Gold is over 10 times more dense than the majority of stuff in any riverbed.
What does that mean? It means that given even the slightest opportunity, gold will sink to the bottom.
The bottom of what you ask…
Well, the bottom of where ever it happens to be. That means that if it’s in the river bed, it’s going to eventually find its way down to the bedrock at the bottom of the river channel if it doesn’t get washed out to sea first. If it’s in a bucket full of sand and gravel you’ve dug up, it’ll settle quickly to the bottom if you disturb the contents too much. If it’s in your pan, it’ll quickly and reliably find its way do the bottom of whatever you have in there with out too much prodding on your part.
So, now we’ve hit on the “bottom line” so to speak, and the magic secret of panning for gold. Remember, gold is ten times “heavier” (actually more dense) than most of the stuff in the river and over twice as “heavy” as the next most common metal in the river, Iron. Plop a handful of river gravel and sand into your pan, submerse it in water, stir it around a bit, give it a couple shakes and you can almost guarantee that if there’s gold in there, it’s now at the bottom of the pan. In fact, using techniques we’ll go into in the next episode, once you wash away the majority of gravel and sand, you’re likely to be left tiny fraction of the original volume of material, and it will likely look like pure black sand. The first few times you try, you’ll probably say to your self “Rats! No Gold!”. But wait… that black sand is mostly if not all Iron. And what did we say about the density of gold compared to iron… that’s right, if we’ve done our job right, and if there was gold in the pan to beginning, then it’s probably still there now, just hiding underneath the black iron sand.
It’s a big thrill the first time you separate out the black sand and find the flake of gold clinging to the bottom of the pan. Even though most finds are just flakes, and not the thumb size nugget that make national headlines, it’s still a lot of fun to find them.
Next episode we’ll be taking a look at common equipment used for recreational gold panning, where to get it, and how to use it.
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