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Tom T.

I'm a brand new newbie! Last weekend, I bought a bucket full of geode from a garage sale. There's one piece that already had a small hole that was filled with dirt.

I've cleaned out the dirt by gravity & garden hose spray. I've also cracked open it to find out that the cavity was lined with the clear & yellowish (probably iron stain) crystals, and quite nicely!

My question is how to clean out the dirt particle inside the cavity? Can I use Oxalic acid to clean out the iron stain? Would that damage the geode itself? Since it was already filled with dirt before I get it, I assumed that there would not be any concern about its other internal mineral that still survive except the hardy crystals. Is that a safe assumsion before the acid bath?

Thank you for your help.

Mike Streeter
Hi Tom,

Welcome to the board!

First, get yourself a power washer to clean out the inside and outside of the geode. A power washer is the best way to remove dirt and other debris from between quartz crystals. However, be careful about how much pressure you apply (use a fine spray) if you the geode contains delicate minerals. Wear sturdy gloves and safety glasses if you have to hold the geode to spray it.

To remove the iron oxides, you could first try soaking the geode in Super Iron according to the following procedure:

1. Submerge the specimens in a tub or other air-tight plastic container with very hot water. Sometimes if I am concerned about shocking and cracking of minerals such as large quartz crystals, I will heat up the specimens in the kitchen sink using the water sprayer. I will start with a warm spray and gradually (over about 3 to 5 minutes) turn up the heat to maximum.

2. Sprinkle in a copious amount of Super Iron Out to the hot water (there is no rule on how much). You MUST add the Super Iron Out outside due the noxious fumes that will be emitted. I highly recommend that you wear a half-face respirator with chemical cartridges when you add the Super Iron Out. You will certainly need a respirator when you pull the specimens out of the solution. I have learned to hold my breath when adding the powder - I will sprinkle in the powder, quickly walk away to avoid the fumes and catch my breath, return while holding my breath to put a lid on the container, walk away again to avoid the fumes and to catch my breath and come back when the air has cleared to bring the container inside so that it doesn't freeze (freezing will destroy the specimens). My somewhat-lame "holding my breath" method does not work for retrieving the specimens. Also, be aware that whatever clothes you are wearing will absorb some of the odor from the Super Iron Out.

3. Allow the specimens to soak in a warm place for one to several days

4. Check the progress after a day (wear a respirator when you pull the lid off or the fumes may knock you on your butt or, worse, stop you from breathing!!!). Use rubber gloves to retrieve the specimens from the solution. You can use a toothbrush under the kitchen tap to remove some of the iron oxide that has been weakened by the solution.

5. Repeat steps 1-4, if necessary (it most often is with heavy iron oxide coatings).

6. When completely clean, soak the specimens in clean water for a day or two, changing the water out one of more times.

It has been my experience that the Super Iron Out method is generally less effective and more expensive than oxalic acid, but is probably the safest way, in terms of potential crystal damage, to treat specimens. Hot oxalic acid will destroy water soluble minerals such as calcite, aragonite, etc but it works great on plain quartz geodes.

Good luck!

John Cornish
Hi Tom,

One more word about oxalic acid...

NEVER EVER use it with carbonate minerals (calcite, aragonite, etc.) as it will attack these minerals and then redeposit them as an impossible to remove coating. Oxalic is great for straight quartz, but is a death wish for carbonates.

Like Mike mentioned, I love Super Iron Out and typically order it from the manufacturer in quantity.

Good luck with your cleaning, be safe and have fun! All the very best,

Tom T
Thank you, gentlemen, for your advises. Where do I go to buy the "iron out"? Would the local Home Depot, Lowes or Menards carry it?

I believe Lowes and Home Depot carry SIO in the cleaning products isle. Otherwise, look in the plumbing isle- SIO is made to remove stains from porcelain. Good Luck!
Hi Tom,
Just put your zip code in this box and select Super Iron Out as product.
Click Here
Good luck!!
I have a question, is there anything that you can use to clean crystals that maybe calcate in makeup? I am such a newbie at all this stuff. I am trying to get money up to buy books and tools and use, I search the internet and now I have found this wonderful site where I can "pick" you wonderful Rock "masters" brains! I have several geodes I bought from Liberty Kentucky. Actually thru Ebay I bought 20. I have been slowly breaking them with only a hand held sledge hammer and a flat head screw driver. I know your smiling, but I am trying to get funds together to buy more stuff that I need. Some of my geodes have been very nice. Not Keokuck quality, but I think they are cool. Some have what I have heard is probably a iron stain, they are crystal but look like some of them are golden or yellow in color. When I soak them several different times, sometimes yellowish water comes off. I also have the ones that are just sort of nodule looking inside and bumpy and covered with what looks like cinnamon stuff. Doesn't wash off, doesn't scrub off easy. Believe it or not I sprayed some tylex bathroom cleaner on it and a little came off. But I am afraid they are calcate and don't want to hurt them. Someone even said white vinegar helps. I am definately hooked on my geodes. I have only saved 3 so far that I adore and can't give away. The others I have generously given to many different friends at work. (I work with over 500 screeners at Kansas City International Airport. I am a Lead Screener Supervisor) I can't help myself from is great..people just seem to love looking at them...and when someone really likes one...I give it to them. People you would least expect are "bitten" by the rock lovers bug. Oh well thats all for now. I get nervous about the respirator stuff you talk about. Don't want to poision I already have asthma. Thanks for tolerating such a unschooled soul...but I am trying to learn fast! I guess you could say I am "in too hard rock.." sorry bad pun.
Tom T.
Looks like every body in town has the "super iron out"! That's a great link! Thanks Everett!

Tom T.

I've finally bought the 5 lb bottle of Iron Out. Now how much do I need to put in a 1 gallon of water? I need a starting point from somewhere! "Copious" amount for a newbie like me makes my hand shaked! Please help.

Mike Streeter

OK - For one gallon, try about 1-cup of super iron out.

Tom T.

Finally, I got some time to tend my new hobby!

I'm still not sure of what I got! I've attached 2 pictures so you can help me out. The larger "bumps" to the upper right of the geode is in question here! Is that calcite or just quartz like the rest of the yelowish crystal? If it's calcite, then would I run the risk of dissolving the calcite if bathing long in the Iron Out solution?

Thanks for your help.

Tom T.

Attached Images
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George Finley
Sherri a Airport Screener. It re mined me of when I gave a nephew a large Clam Fossil and a Large Rose Rock that he packed with the Clam over the Rose Rock. It look like a unknown and they had to check it out. The Screeners got real upset until he told them what it was and showed them. Now you can't take a large rock on the plane as you may use it to hurt someone. Keep up the screening at our Airports. Geo.
Mike Streeter
Tom - The picture is a bit blurry, but the larger crystals do look like calcite. Super Iron out won't harm calcite.

Hello All,

I have been reading about cleaning geodes and there is one question I don't see answered. I am an Earth Science student at the local university and rock and fossil hunting have fast become a favorite hobby. Recently my Earth Science club did some rock cutting on the saws in our dirty lab. One of the saws used a water soluable oil. Now this stuff stinks terribly and I cannot get the oil off the geodes. I was told to use muratic acid either under a vented hood in the lab or outside away from the house. How long should I let them soak and at what dilution? Never could get a straight answer.
Mike Streeter

If the oil is water soluble, then all you should need to clean them is hot water - a strong spray would work best. If the oil is not water soluble, then you could try using hot water along with dishwashing liquid - wash then soak the geodes overnight in hot soapy water and then rinse with clean water. I would not use muriatic acid for this task.

Bruce B
I was just told last weekend at a show that you can use the new dawn dish soap just like you are washing dishes. Just fill a bucket with water and dawn and it takes the oil and smell right off the geodes.
Hello Mike, Thank you for your insight. I tried using very hot soapy water but the oils have premiated into every nook and cranny of the geode. I will try again only over night as you suggested as I only soaked them for three hours the first time. If I get them cleaned up well enough, I'll send a picture of them. Thank you again, I appreciate your advise.
Brenda Zabriskie
I'm sorry Bruce, I didn't see your comment until after I replyed to Mike. I will try the Dawn, I know it is suppose to work on really greasy dishes maybe it will work on my geodes.

Hi. We just recently returned from a trip to the Hausser Geode Beds near Blythe, CA. Wonderful experience that I highly recommend. On the way to our adventure, we ran into some rock hounds that said if you put baking soda with vinegar inside the geodes, they clean up nicely. Now.... I too have a question. Some of the stones we got are actually Nodules and have agate inside- what is the best way to cut these?
Rock Hunter
Hello McRocks experts!

I read your replies to Tom about using Iron Out.  Do you think that is also my best option?
I attached two photos of my specimens.  I have about twenty others, but they are all the same make-up.  I found them in the river at Sam Baker State Park in Missouri.  They look to me like a combination of agate and chalcedony, but I'm not certain.  The scientist in the nature center said agates like the one in front are not native to the area and probably washed down from all the snow they got up north this year.  
Would Iron Out disintegrate the crystals? 


Rock Hunter

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