Wouldn’t it be nice if all the rocks we brought home looked like the shiny clean specimens we see in Rock Shop display cases? Well, you know they don’t, but there are things we can do to make them look better.

Rocks and minerals are gathered from a natural setting or a riverbed. Some rocks and minerals we find in mines or quarries. They not only are covered with clays, they can also be covered with oxides or layers of a mineralization of quartz or calcite. In order to really enjoy their appearance, they need to be properly and safely cleaned. Some simple steps can accomplish this, some not so simple steps and some steps can be dangerous. Whatever you use to clean them, use some caution. You will need eye protection in all cases. Don’t take a chance with injury to your eyes. In many cases you will want to wear a long sleeve shirt to protect your bare arms. A small splash of a chemical on your skin can be painful and damaging. A chemical droplet will continue to burn into the inner skin layers until you wash it off. Rubber gloves are a must with all cleaning solutions. The best method to clean some minerals is to submerge them in some type of a solution. That solution more than likely will be some type of an Acid. Acids Can Be Dangerous and can damage not only by contact but also by inhalation. By mixing solutions with other unknown substances can be dangerous. READ THE INSTRUCTIONS on all cleaning solutions and understand them. KNOW what you are doing before you do it. Equally important is knowing the first aid steps to take in case of an accident, as they do happen. Have clean water available before you begin as a safety precaution.
There are some rocks or minerals that can be damaged by water or by other certain cleaning solutions. A list of those will be forthcoming later in this article.
The first method I use in cleaning my rocks is to take them to a car wash, in a couple of those plastic carry containers. The ones the milk men carry their milk in. A high pressure soaping will clean the majority of the dirt and slime off. Make sure you rinse them. When you get them back home and there is still dirt and mud in some of the indentations and cracks, soak them in dish soap and water for a couple days, making sure there are no minerals in the bunch that are listed below. This will loosen the mud up, and you may not have the need to use stronger chemicals.
One can usually find items at home to help clean them further. Alcohol, cotton swabs, tweezers, toothbrush and dental picks are good tools to use along with a brass brush. A brass brush is rated about a 5 on the Moh’s list of hardness. Since the majority of the rocks are 7 – 8, a 5 will not hurt them. A regular steel bristled brush could cause some scratches. One method you do not want to employ while cleaning rocks is to clamp them in a vise. They can be easily damaged by the jaws. Hold them in your hand, or for bigger specimens, lay them on a table. Inspect them after cleaning, as it may reveal a feature that was not seen prior to cleaning.
If using Acids to clean with, you need face and eye protection, rubber gloves, arm protection, as well as hard rubber tongs to place your specimens in the solution and to remove them from the solution. DO NOT use your bare hands for anything! DO NOT just plunk your specimens in the canister. Lay them in softly with the tongs. DO NOT use a metal container or metal tongs. KEEP your face away from the top of the container and DO NOT breathe the vapors. I have been using a plastic ½ gallon ice cream container. They work fine and the solution will not eat through it.


This is the quality or the properties, of being soluble, and their relative capability of being dissolved. Plain old tap water can damage some minerals.


The following is a list that you would want to be careful of when cleaning, as they can be damaged or partially dissolved in water alone. They are:
Autunite; Halite; Colemanite; Fosgenite and Gypsum. A quick dunk and then drying them right away should not be a problem.
Do not let them soak in water overnight.


The following list contains those minerals which are not damaged by acids or certain cleaning solutions. They are:
Anatase; Barite Beryl; Cassiterite; Celestite; Cinnabar; Diamond Diopside; Distene; Epidote; Gold; Hornblend; Millerite; Quartz Rhodonite; Rutile; Sulfur; Talc; Topaz; Tourmaline; Vesuvianite and Wolframite. As you can see the list is rather small considering there are over 4000 known minerals.
However, if any of the above minerals have some particles in them that can be soluble in water, that part of that particular mineral can be dissolved. Keep that in mind.
The majority of the minerals not in the above two lists, can be damaged by use of Clorhidric Acid, Nitric Acid, Sulfuric Acid or Fluorhidric Acid.
When cleaning specimens which are insoluble in acid, use the following cleaning solutions in the order as given.
1) Iron Out. Iron out is probably the safest cleaning solution one can use. This can be purchased at Walmart, hardware stores or most large chains. It can be called Super Iron Out. However be advised it can relieve your specimen of some color. It does not contain harsh or abrasive chemicals. It is great for removing iron stains on quartz. Just follow the directions as on any solution package.
2) Oxalic Acid. Oxalic acid is a white crystalline powder. It is a poison and is dissolved in water to make it work. It does have the ability to dissolve fine grained iron mineral stains and will do a pretty good job on cleaning your brown rust covered quartz. A drawback to using Oxalic Acid is when you are done with it, do not dump this stuff down the drain. Don’t dump no cleaning solution down the drain. Dispose of it properly. If there is a disagreeable agent in the drain or drain pipes, you may end up with an ugly discoloration on the ceiling over your sink, or find your sink embedded in the ceiling! If you are in the way of that disturbance, you could loose your sight and receive chemical burns wherever the blow by touches you. Be very careful! Specimens can be left to soak for several days in Oxalic. When the specimens are removed from this solution, they need to have a thorough cleaning in water.
Do not substitute other chemicals just because they have a similar name. They are different! Oxalic Acid is not a gentle chemical technique for removing staining films, but it is much gentler than Muratic Acid. It will work.
3) Muratic Acid, also called Hydrochloric Acid or Pool Acid. It is Hydrogen Chloride that has been carefully dissolved in water. Before you use this method, go to Wikipedia and read all it says about it. Be Informed! You can buy this acid in any hardware store. When you handle Muratic Acid, (hydrochloric acid), you should use rubber gloves and eye protection and it should NOT be used it in a confined area like your home or garage. It is some nasty stuff but it does work. Extreme care needs to be practiced while using it. I for one do use Muratic Acid as well as Oxalic Acid. I have for years. I understand both of them! Specimens can be left to soak in Muratic for several days. Once removed, the specimens need a thorough cleaning in water.
A quick dip in whatever solution you use for 15 seconds to 1 minute and thoroughly washed immediately will give you an indication if a chemical is damaging. The damage indicator is that the color could change and you may observe or hear some cracks. If unknown whether it is damaging, do not use it for prolonged periods of time.
Let your specimens soak in clean water for a few hours after cleaning. You may want to repeat this rinse process several times.
All acids must be used with respect.
The cleaning solutions can be stored in a plastic jug with a tight fitting lid. It is advisable to write on each jug what the contents are. Use a permanent marker. DO NOT mix cleaning agents! Do not overuse the durability of a plastic jug. They do get brittle. I suggest you have a container of powdered limestone on hand, near where you store your agents. In case of a spill, you can use limestone or marble chips to neutralize the acid, then wash the area thoroughly with water. Upon adding extra limestone, and you get no more bubbling, the acid is neutralized.
NOTE: Always add the acid to the water, NEVER add the water to the acid, when mixing a cleaning solution. DO NOT use it straight. It needs to be diluted.

I employ the use of a sandblaster on some of my rocks and minerals. It does a very good job. With the use of duct tape, strategically placed on softer minerals, a sandblaster can create some great designs on the exposed rock. You will find you can be thrilled with the pattern you can create.
They do have an ultrasonic cleaner on the market that people like. I do not use one of these so cannot give a yes or no on it.
An Air Scribe is also a great tool. I use an air scribe a great deal of the time in carving. The only drawback is that you need a decent sized air compressor. An air scribe is a tool much used by paleontologists.


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