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How To Clean Geodes And Thundereggs...The Easy Way!

Cleaning geode rocks and crystals


If you’re reading this post, then it means you’ve been able to get your hands on a few geodes. First of all, congratulations!  It’s exciting to go out and dig up geodes out in the wild...right where they formed. 

But now that you’ve got your new collection of geodes, it’s time to clean them up since they’re probably covered in dirt and grime.

And that’s exactly what this post is about. We’re going to go over a few of the easiest ways to clean geodes and thundereggs.  

So let’s get right to it!

How To Clean Geodes and Thundereggs

There’s all different kinds of ways to clean geodes, from as simple as running them under water with a scrub brush to using special chemicals.

But regardless of the method you use to clean the geode, you must be sure to use protective eyewear, gloves and respirator if using chemicals to clean them.

Easiest Method To Clean A Geode

The quickest and the easiest way to clean your geodes or thundereggs is to just wash them with plain old soap and water.  I’ll usually take a soft bristle scrub brush to them as well, to get all the dirt out of the cracks and crevices.

After washing the geodes with soap and water, soak them in a bucket full of water that has ¼ cup of household bleach mixed in with it.  Let the geodes or thundereggs soak in the bleach water solution for 2 full days.

The last thing you’ll do is clean the geode with a toothbrush and denture cleaner. An old electric toothbrush works really well for this. Be sure to carefully scrub all of the cracks and crevices with the denture cleaner to get all of that grit that can become embedded deep in those cracks.

Wood Bleach Method For Cleaning Geodes

So you’re going to want to use this method for cleaning geodes if you notice iron staining inside the geode. 

But first, you need to keep in mind that wood bleach is toxic, so you will want to wear eye protection, gloves, and a NIOSH-approved respirator mask. The other thing to keep in mind is that wood bleach is extremely corrosive, so don’t use it in metal containers.

The first thing you want to do is rinse the geode or thunderegg and remove all of the dirt that you can.

Next, mix up the oxalic acid solution. For this you just mix ⅛ cup oxalic acid for every 5 liters of water.  Then soak the geodes in this oxalic acid solution for several hours.  But don’t let the geodes soak for much longer than this as the oxalic acid can damage the geode.

If after a few hours the geode is still stained with the rust color, you can try soaking them for an addition hour or two.  But if you’re going to soak them for a second time, I would try increasing the concentration of the solution as well by just a little.

Finally, after soaking the geodes, rinse them off completely with warm water.

Oxalic Acid and Calcite Crystals

You should know that oxalic acid can damage calcite crystals and carbonates. If you suspect that you have either one of these, what you can do is simply brush on a small amount of diluted oxalic acid solution, then immediately wash and soak the geode with warm water afterwards.

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3. The Best Rock Hammer For Amateur Geologists and Beginner Rockhounds