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    -   by George Campbell    (

There has long been a controversy among mineral collectors over the issue of cleaning specimens. Many of us enjoy the pristine beauty of a specimen where all extraneous material has been removed from the central crystal or crystals of a mineral. Others believe that specimens should be left much as they emerged from the earth, complete with the accessory minerals and coatings. It's a constant dilemma, and one for which there isn't an easy answer. Is there one correct answer? Perhaps not.

On the Clean Side
Many collectors, especially those who use their silver pick to acquire specimens, never see a specimen looking as it does when it is originally collected. That perfect quartz crystal from Arkansas was once coated with thick mud, iron stains, and perhaps a bit of calcite or other stuff that obscured the transparency and luster of the original specimen.
The original collectors have bathed the specimen in acid, subjected it to the kind ministrations of a power washer and done other things to get it to the state you see on the dealers' tables at your favorite mineral show. Is that wrong? By no means. It is precisely the transparency and luster of the quartz crystal that we, as collectors want to see from that specimen. Uncleaned, its value and beauty would be much reduced.

The same thing would apply to any specimen where the central goal is to be able to view the crystal or crystals of the primary mineral with nothing standing in the way. Removing mud, dirt, and other coatings is a desirable thing, in many cases, allowing a full view of the beauty of the mineral.

On the Other Side
There are other specimens, however, where such cleaning is undesirable and may even ruin the specimen entirely. Most collectors have seen the calcite specimens from Mexico which seem to have rounded, rather than sharp edges on the calcite crystals. This is caused by giving the crystals an acid bath in an attempt to make them more lustrous, and to remove coatings of other carbonate minerals such as dolomite. Since the cleaning treatment destroys the outlines of the crystal, the specimen loses its natural appearance and becomes something completely different...something manmade, in a sense.

Similarly, I have seen fluorite specimens that were once coated, all or in part, with a druse of quartz, calcite, or dolomite, but which had been carefully cleaned to remove all vestiges of the natural coating. While this does expose the fluorite, it destroys what was a natural growth of another mineral and alters the specimen so its original state is gone. Since there are plenty of fluorite specimens without such an epimorphic coating, there is no reason to ruin what was a perfectly fascinating specimen, just to reveal some fluorite crystals.

In a similar way, some specimen preparers remove all sorts of accessory minerals in an attempt to expose more of what they consider to be the main mineral or crystal. By doing this, the specimen becomes useless as a scientific specimen and information about its paragenesis is lost forever. Indeed, in the quest for beauty, rare and interesting minerals are lost through overcleaning, and the specimen reveals nothing of its original complexity.

Even Worse
Without even mentioning undisclosed repairs and created specimens, where foreign crystals are attached to a specimen, there are even worse preparation techniques used on specimens. Quartz and calcite crystals are sometimes polished on a lap to remove surface markings, etching, and even growth patterns in an ill-thought-out attempt to "beautify" a specimen. Even worse, unterminated crystals are sometimes given new terminations on a lap, or a plain pinacoidal termination may be given beveled corners. At a casual glance, if the preparer is careful, the customer will never notice what has been done, although close inspection with a loupe or microscope will reveal the regular markings of machine polishing. While this practice may pass muster with those seeking crystals for new age purposes, it is unacceptable for collectors.

Another technique sometimes used to beautify a specimen is oiling, which can add to the luster of a crystal or even fill internal flaws, hiding them from the eyes of the customer. Such practices are fraudulent, unless they are fully disclosed. While oiling is necessary on crystals of minerals like thenardite or blödite, to prevent deterioration, it should always be disclosed by the seller. Oiling of emeralds or other beryl crystals should never be done, even if fully disclosed. Heat treatments to alter colors, and other such techniques are also common and specimens which have received such treatments should be rejected by serious collectors.

A Compromise
While over cleaning of specimens will always go on, partly because some collectors demand only aesthetic specimens, a collector should ask how much cleaning has occurred. Wherever possible, the original collectors or miners should maintain some specimens in an unmodified condition, or with cleaning limited to washing off mud or clay. In that way, collectors who prefer specimens that retain their original condition will be able to acquire such specimens for their studies. In many cases, it's desirable to have both a fully cleaned and an uncleaned specimen in a collection, for comparison.

For the collector who purchases specimens from dealers, it can be a difficult proposition to determine how much cleaning and preparation has been done. Since a specimen may pass through many hands before a collector purchases it, the dealer you buy from may not actually know how much cleaning has been done, but it never hurts to ask. Also, inspect specimens closely, using a loupe, to try to detect alterations. This is especially true for high-value specimens. Look for evidence of lapidary work.

Finally, collectors can begin to ask for specimens that have not been cleaned and prepared to excess. If this is done, dealers will be encouraged to present more specimens in their original condition, or those that have been only lightly cleaned. For sheer scientific reasons, this is desirable, since it's essential that specimens retain their accessory minerals and coatings if the paragenesis of the specimen is to be understood. In some cases of classic, but closed localities, no specimens at all exist in their original condition for study. And that's a shame.