Simple Mineral Cleaning Techniques

Joe HeadshotThis page contains a few cleaning tips for typical Pikes Peak batholith minerals that are likely to be found on our mining claims.

NOTE: I recommend hiring someone for professional cleaning and mineral preparation in the case you find some very special mineral specimens. We do professional cleaning and preparation at a reasonable rate. Unfortunately, any professional cleaning may take a very long time due to the processes that are necessary. You may be aware that we spend well over a year on cleaning and preparing some of our pockets. We DO NOT do any cleaning during the mining season (roughly end of May through first part of August). There is no time and we cannot safely monitor the processes.

There are many techniques for cleaning different types of minerals and for the conditions the minerals are found in. Many mineral clubs have presentations on mineral cleaning and have members who are knowledgeable. Also talk to other field collectors about the techniques they use. We use a combination of techniques and specialized equipment for our cleaning lab; however, there are some easy and inexpensive techniques you can use.

The tips I give are for microcline (amazonite) feldspar, albite (cleavelandite) feldspar, quartz, goethite, and fluorite. Where applicable, I will discuss special techniques for each species.

Initial Cleaning

Carefully wash all specimens. Try soaking them in a detergent solution such as a bubble bath solution or dish detergent solution. Soak for a day or more when possible. Use a soft (very soft) tooth brush and remove all clay and soil that is possible. When washing goethite blades or delicate crystals of any sort, you may want to just swish in the detergent solution and avoid the brush. Rinse and soak longer if necessary. A lot of clay and oxides can be removed with careful washing. Most people do not do a thorough washing. Rinse and lay out on paper towels to dry.

Using Super Iron Out

This is a commercial cleaning product that contains sodium hydrosulfite and sodium bisulfite. It is a skin and eye irritant and the vapor is harmful. DO NOT HEAT Iron Out. Read the caution label before using and follow all use and directions on the label. I CANNOT assume any liability or responsibility for your misuse. Always use long, chemical resistant gloves and eye protection. Always have good ventilation.

The action of this product on most minerals is gentle and causes little or no damage to the silicates normally found in the Pikes Peak batholith. In general, the Iron Out chemicals bind with the iron oxides and draw them off the minerals. It does little good on anything else, but most of the cleaning you will need to do is for the iron oxides.

The one drawback to using Iron Out is that it usually takes a long time.

Fill a tub (that has a tight-fitting lid) with room-temperature water (the same temperature as your minerals). Carefully place your specimens into the tub, ensuring they are not in contact with each other (avoid damaging tips, etc.). Add about two tablespoons of Iron Out crystals (it comes in a white, dry crystalline powder) per gallon of water. You can mix it if you would like, but it is not necessary. It will diffuse into the water. Quickly place the lid on and place the tub in a safe place.

The Iron Out will smell like rotten eggs, and you may have some dust and vapors coming from the solution while mixing. I try to avoid breathing vapors and mix my solutions out of doors or with a fan going. After the lid is on, there is no problem.

Allow your specimens to soak in the solution for 2 to 3 days.

Now, here’s the closely guarded secret. Iron Out is consumed rather quickly and needs to be recharged. Go ahead, after 2 to 3 days, and add more Iron Out, about the same amount as you used initially. Note the condition of your crystals at the same time. You can (using rubber gloves) examine one or two to see how they are progressing, but the specimens will rarely be done after one session. It will take several sessions. After adding more Iron Out, slide the tub back out of the way. Wait another 2 – 3 days.

You can recharge the Iron Out three to four times before changing out the water. Some specimens may be done after the first session. For those not done, change out the water and recharge with Iron Out as you did for the first session. It is important to rinse your specimens in same temperature water. I use a solution of water with baking soda to get rid of the sulfur smell. Between sessions, I also use the tooth brush to get off the residues. This allows the Iron Out to have more access to the remaining oxides on the specimens.

For those complete specimens, go ahead and remove them. Rinse in baking soda solution, rinse in water, and allow to dry.

Depending on the amount of iron oxides on your specimens, you may need three to four Iron Out sessions. Now if you’ve been counting days, that’s up to a month and a half.

Occasionally you will notice a black-green residue on the minerals you are cleaning. This is the iron oxide that has combined with the Iron Out. Generally you can remove most of this with the tooth brush and a fresh solution of Iron Out. If not, where applicable, use a wire brush (avoid using wire brush on fluorite and goethite.) The black-green residue might need to be removed with a separate cleaning step using an acid.

When you need to dispose of the Iron Out solution, flushing it with water on open ground should be sufficient. It is a household cleaner. A small occasional amount should not be a problem.

Using Citric Acid

To remove the Iron Out black-green residue, try mixing a tablespoon of citric acid crystals with a quart of water. At room temperature, soak the specimens for a day or two in a covered crock pot. Do not heat. Neutralize in baking soda for an equal amount of time. This normally takes care of the black-green, but not always.

Both citric acid and vinegar will also remove the metallic brush marks.

A citric acid solution can be used for several Iron Out sessions. A small amount of citric acid can be disposed of as any household waste.

Silicate Residues

After cleaning in Iron Out, most specimens will show powdery silicate deposits on all the crystals. You can remove most of these mechanically.

The best method for a few specimens is a wire brush and elbow grease. Again, this can be problematic with goethite, fluorite, and some other sensitive minerals. Experiment with different types of brushes.

The wire brush marks can be removed in the same manner as the black-green Iron Out residues.

Better Yet…

If you have problems with Iron Out residues and silicate deposits, we can do these final cleaning steps for you at a very reasonable price. We also do repairs and can trim your pieces.

Good luck on your cleaning.

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