Chrysoberyl, Teofilo Otoni, Minas Gerais, Brazil
This was the first thumbnail mineral I purchased. It is a cyclic twin chrysoberyl.
I have been asked about cleaning minerals. First ask the dealer when you purchase the mineral. If that fails here are a couple of pointers for purchased minerals that are just a bit dusty. I will not cover cleaning mine run minerals because that can get a bit complicated. (mine run minerals- mineral straight out of the mine with all the matrix and dirt attached)
Prevent dust build up. The more you can prevent dust build up the less you will have to clean your minerals. Every time you clean a mineral you take the risk of harming the specimen. So store the mineral in a closed case, perky box or other contained environment. Prevent people, yourself included, from excessively touching your minerals. Finger oils dull surfaces and act as a dust magnet.
1) Research the mineral enough to make sure it is not reactive with water or water soluble, think halite. Water soluble minerals usually can be cleaned with isopropyl alcohol.
Water Soluble Mineral Species - John Betts - Fine Minerals ...
2) Are the crystals fine and acicular (needle like), think aurichalcite. Though some of these minerals can be washed I prefer that you hold the mineral upside down and gently blow away the dust. If you are very careful you can use canned air or a keyboard vacuum cleaner.
3) For the water washable minerals: Make sure the mineral and the water are at room temperature. Sudden changes in temperature can cause many minerals to cleave. Start with water and no soap. Swish around in the water and dry the mineral upside down. You dry it upside down so any dirt can drip off the mineral. Of course be sure the mineral can stand to be placed upside down. Common sense has to prevail sooner or later.
If swishing in water did not work add a little dishwashing soap to the water. This is not the dishwashing soap you use in an appliance but the kind you hand wash dishes with. Gently swish, then rinse. All water at room temperature. That did not work. Check the hardness of the mineral to make sure it is not ultra soft. If not you can use a soft toothbrush to gently scrub the mineral. Then rinse. That will usually clean most minerals.
4) Ultrasonic cleaners are fine if the crystals are firmly attached to the matrix and the matrix is rock solid. Ultrasonic can break fragile minerals or minerals on a fragile matrix. If you can use an ultrasonic it will remove fine dust particles deeply buried in the crevices.
5) In all cases make sure the mineral is thoroughly dried before returning to the display case or storage. Residual moisture can seriously harm some minerals, think pyrite. On humid days I place the mineral in front of a fan to be sure it is completely dried.