Treasure Hunting

Every now and then you’ll hear stories about people “accidentally” stumbling on a nice supply of gold without even looking for it. Experienced gold panners and gold miners know just what to look for - after all, it’s what they do. But if you spend most of your time hunting for quartz and agates, how do you know if what you’ve found is real gold or not?

Iron pyrite, copper-iron pyrite, and mica (otherwise known as fool’s gold) can all look quite a bit like gold especially in the bright sunlight. There are a couple of quick and easy tests that you can do in the field to try to determine if what you’ve found is real gold or yet another score of fool’s gold.

The Fingernail Test for Gold

Probably the easiest test in the world for a gold-appearing rock is the fingernail test. Just poke the tip of your fingernail into the rock. Real gold is actually pretty soft and can be easily dented with the fingernail. If you poke pyrite or mica with a fingernail, it will just flake off or have no effect at all. If your fingernails are way too short for this, you can perform the same test with the tip of a pocketknife or screwdriver.

The Hydrochloric Acid Test

This test requires a little more caution, but it’s still pretty simple and works better for smaller objects or rocks that you think may be covered with gold dust. (It’s pretty hard to poke dust with a finger.) Very carefully, place a drop of hydrochloric acid on the area of the rock that you think might be gold. If it bubbles and fizzes, chances are that you’re out of luck. The acid should have no effect on real gold. It’s still possible that there is some pyrite or mica mixed in with real gold causing the fizzing to appear, but that would be pretty rare.

If you’re wondering where to purchase hydrochloric acid, you’re not alone. Actually, it’s not that hard to find at all. It’s sold in many home stores in the swimming pool section under the name muriatic acid. Hydrochloric acid and muriatic acid are the exact same thing - muriatic acid is just an older name for the substance. I’m not sure why pool supply stores choose to use this name rather than the more modern one. Anyhow, muriatic acid is often used to help adjust the ph levels in swimming pools. If you have trouble finding it, just ask one of the sales people. Definitely remember though that this is a very strong acid and you should use extreme care when using it. If any gets on your skin or clothing, rinse the area immediately. In case you burn yourself, treat it as you would any serious burn and contact a physician if it is serious.

(Photograph courtesy of Aramgutang from Wikimedia Commons.)