It’s time to clean those beautiful Arkansas quartz crystals you collected at the mine. You will need to get all of that clay removed. Do not, and I repeat, do not attempt to clean the dirt off in your sink. The clay will quickly plug up the drain and your plumber will love you.
Let Crystals Dry
Lay the crystals out to dry on an old tarp or plastic bag. Turn them over until they are completely dry. Crystal clusters will take more time to dry than points. You could also dry them on a ¼ inch mesh screen covered frame (they are easy to make). When the crystal is dry enough to clean the clay will look cracked. Rinse thoroughly with a garden hose (both sides). Dry them again for a few more days and rinse again completely. It is very important to remove all of the clay.
Crystal points are easy to get clean, but a cluster can require some additional work. Clay settles down deep between the points on a cluster and can be hard to get out. Using a dental pick or similar tool you can carefully pick out this remaining clay.
Cleaning Crystals Using Oxalic Acid
Most crystals will be completely or partially coated with gold/brown iron oxide. This coating can be easily removed by soaking the crystals in a mild oxalic acid solution. Oxalic acid can be purchased from most mineral dealers in Arkansas. While oxalic acid is mild, it is dangerous to breath. Use it outside, in a well-protected area away from children and pets. Always wear heavy rubber gloves and safety glasses when working with the oxalic acid solution. The oxalic acid solution is made from 3 parts water to 1 part oxalic acid.
Wearing your heavy rubber gloves and safety glasses; place your crystals in a plastic tub or bucket (not white) with the acid solution. Make sure the acid solution covers your crystals. Cover the containers and let the crystals soak for 3 to 5 days in the sun. Remove the crystals from the containers when they are a cool temperature making sure to wear your heavy rubber gloves and safety glasses. Rinse the crystals thoroughly. You crystals will look spectacular. If there is any iron oxide still showing, soak some more.
Heat speeds up the cleaning. You can use a crock-pot or have a custom-cleaning vat made. Place your crystals in the pot or vat; add cool water and a few ounces of oxalic acid. Add more cool water until the water is above the crystals. Cover and set the temperature control to medium. Bring the oxalic acid solution to a simmer which usually takes 3 to 4 hours. Turn the pot or vat off and allow it to cool down overnight. Make sure to heat clean your crystals outside, the vapors are poisonous and should not be inhaled. The next morning, remove your crystals while wearing heavy rubber gloves and safety glasses. Rinse the crystals thoroughly with cool water and gaze at their beauty.
Safe Disposal of Oxalic Acid Solution
Your acid solution can be reused until it turns very green. At that point, the old solution needs to be neutralized and disposed of. Slowly add baking soda to the solution to neutralize it. When the solution stops fizzing, it is completely neutralized and you can dump it on the ground.
Things to Remember
- Make sure the oxalic acid is clearly marked and that you have a receipt for it. It can appear like an illegal substance!
- Always follow the instructions that come with the oxalic acid.
- Always wear safety glasses and heavy rubber gloves when you are working with the oxalic acid solution.
- If you splash the acid solution on yourself, rinse it off immediately.
- Do not inhale oxalic acid fumes. The fumes are very dangerous.
- Always clean your crystals outside in a well-ventilated and protected area.
- Always keep your oxalic acid solution covered to prevent pets and wild animals from getting into it.
- The crock-pot can never be used for cooking food again.
- Always neutralize the oxalic acid solution with baking soda before you dispose of it.
- Crystals can crack or fracture very easily.
- Do not place a cool crystal in hot water.
- Do not expose a hot crystal to cool water or air.
As you travel throughout this great land of ours, make sure you refer to your specimens as the mineral quartz crystal. We were stopped once on our way to Illinois. The officer asked what we had in the van. I answered “crystal” and he stepped back, not sure what to do. Quickly, I changed my answer to “the mineral quartz crystal”. After showing him what it was we were allowed to go. So be sure to answer carefully! By the way, never tell anyone that you are cooking up a mess of crystal in a crock-pot. Need I say more?