There is an ongoing debate over the issue of specimen preparation and cleaning. Many collectors enjoy the pristine beauty of an isolated crystal where all the associated material has been removed. Others, however, believe that specimens should be left much as they were found, complete with matrix, accessory minerals and coatings. It’s a continuing dilemma, and one for which there isn’t a simple answer.

In Favour of Improving

Many collectors, especially those who rarely collect in the field, seldom see a specimen looking as it does when it was originally found. That perfect barite group from Cumbria was once coated with thick mud, iron stains, and perhaps even obscured by a coating of other minerals. The original finder would have bathed the specimen in acid, probably soaked it in bleach, and done several other things to get it to the state you see on a dealer`s table. Is that wrong? Absolutely not. It is precisely the beauty of the barite that collectors want to see from that specimen. Uncleaned, its value and appeal would be greatly reduced. One argues that a clear view of the specimen by removing mud, dirt, and other material is a desirable thing, allowing the full view of the beauty of the mineral to be seen.

In Favour of Leaving Alone

On the other hand, there are many specimens where such cleaning is undesirable and can even ruin the specimen. Many collectors will have seen calcite specimens which have rounded rather than having sharp edges.This is unwittingly caused by bathing the calcite in acid, trying to make it appear more lustrous. Since the process destroys the outlines of the crystal, the specimen loses its original form and thus becomes something artificial; never found in nature.

Likewise, many collectors will have seen specimens of Weardale fluorite that were once coated, all or in part, by a crust of quartz which has been carefully picked off to remove all traces of the natural coating. Whilst this exposes the crystal beneath, it destroys what was a natural occurrence of a companion species and thus alters the specimen so that the natural state is gone forever. Since there are many natural fluorite examples without such coatings, there is no reason to damage what could have otherwise been a scientifically important specimen, just to reveal some fluorite crystals.

Lastly, the most destructive cleaning method is to remove the crystals entirely from the matrix to which they were once attached. In some instances this may be unavoidable, such as when the specimen is removed from a large mass of rock that is not easily cut. However, most collectors will have seen tourmaline crystals totally devoid of matrix sitting upright upon small blobs of putty. These crystals are simply snapped off the matrix and mounted individually because suppliers think this makes them more saleable. But by doing so, the specimen becomes useless as a scientific specimen because information about its origin is lost forever. Indeed, in their desire to sell the specimen, many interesting minerals are thus lost through thoughtless alteration, and the specimen subsequently reveals nothing of its original form.

It Gets Worse

So far we have considered legitimate, but open to debate, ways of treating specimens to make them appear more attractive. We now enter the murky realm of the obvious, and less obvious, ways of enhancing specimens. Sadly many collectors will have unwittingly become victims of fraudulent practices such as hidden repairs, crystals reattached to matrix and even entirely manufactured specimens, where unrelated crystals and matrix are put together to form a new combination.

However, there are less obvious ways of enhancing the appearance of a specimen, many of which are based on naturally found pieces, but which are then altered to make them appear more attractive. Quartz crystals, for example, are often polished to remove surface markings in a misconceived attempt to beautify a specimen. Even worse, crystals lacking terminations are sometimes given new ones or given new faces to make it more unusual. If the perpetrator is careful, the buyer will never notice what has been done, although inspection with a loupe may reveal the markings of polishing.

Another technique often used to improve a specimen is oiling, which can add to the lustre of a crystal and in some cases hide internal flaws. Such practices are misleading and deplorable. Whilst oiling is necessary on crystals of some minerals to prevent deterioration it should always be disclosed by the seller. Oiling of emeralds will actually damage the specimens irreparably and must therefore never be done even if fully disclosed.

Finding the Middle Ground

Whilst the cleaning and the enhancement of specimens will always go on, because many collectors demand only aesthetic specimens, a good collector should always ask how much and what type of cleaning has taken place. In the ideal world, dealers should always make available some specimens with preparation limited to just washing off mud and dirt. In this way, collectors can obtain both types of material. The most interesting collections are those with cleaned and uncleaned specimens together, allowing their comparison and study. Also, if you collect specimens in the field yourself, keep some in their natural state as a reminder of the condition you found them in.

For collectors who only buy their specimens, the quest to determine the type of pre-treatment can be almost impossible. The specimen may pass through many hands before they are offered for sale. Consequently the end dealer in the chain may not know what the original condition was like. But you lose nothing by asking. Also, inspect all specimens closely to detect fraudulent alterations. This is especially true for high-value specimens. Look for evidence of lapidary work, and a portable UV light often proves useful for detecting glue that has been used to hold the minerals of the specimen together.

Finally, ask for specimens that have not been over-prepared. By doing so, dealers will be encouraged to offer more specimens in their natural state, or those that have only been gently cleaned. It is important for specimens to retain their matrix, accessory minerals and coatings. This allows their formation to be understood, and is particularly important for closed or inaccessible locations, where the specimen may be the only one left available for study. Deliberately losing the means to preserve such facts is scientific vandalism.