Please take note that this short article is just for cleaning QUARTZ specimens. When other minerals, like calcite, are present on the specimen (that you do not want to remove) then NO acid must be used, just soapy water and a toothbrush.

In this case, we want to remove all other minerals on a quartz crystal or cluster:

    1) Leave dirty quartz overnight in soapy water (using dish-washing liquid). Should you use warm water, it should only be lukewarm, otherwise the crystals may crack. Quartz does not like quick temperature changes, or in some cases, high temperatures.

    2) Remove as much clay (or soil) as you can with a toothbrush. I often use a blunt Stanley blade to remove bits of hard clay (just make sure that the Stanley blade is blunt, otherwise you can easily cut yourself). Be careful with delicate quartz specimens. Remove specimens from soapy water and rinse in clean water.

    3) Prepare the acid solution for crystals that need further cleaning: Wear rubber gloves and work outside, as Oxalic Acid is toxic. Take care not to inhale fumes. It is a fairly mild acid, but care has to be taken nevertheless. Take 2 (two) tablespoons of Oxalic Acid; dissolve in 2 litres of lukewarm water. Place crystals in acid solution; cover and place in a sunny spot for at least 3 days. (Oxalic acid is a grainy, white powder and can be purchased at most hardware shops.)

    4) Remove crystals from Oxalic Acid. After removing crystals from the Oxalic solution, leave them in soapy water for a few minutes. Now you can clean them again with a jet of water and toothbrush. You can repeat the process if necessary.

    5) Quartz from some areas are coated with hard clay that may have minerals in that do not respond to Oxalic acid. This is an extension of this topic that we can deal with on another day.

    6) To clean specimens in an acid solution, I have made things easier for myself by taking a small plastic bucket (depending on the size needed) that just fits into a slightly larger plastic bucket. The smaller one must have a handle. Burn holes into the bottom of the smaller one with a soldering iron (or drill holes), allowing the acid solution to easily escape when you lift the smaller bucket from the larger one. Place crystals in smaller bucket; place smaller bucket in larger bucket; carefully pour acid over, covering crystals; place lid on tightly. Only work outside, because of fumes and toxicity.

    7) The Oxalic solution can be used a few times, depending on how dirty the crystals are. Always cover container well, and out of reach of children, animals and birds, that may mistake it for water. Mark container clearly. When dispensing the solution, throw it in a hole in the ground and fill up with soil.