Accepted practice or consumer scam? Continued in the article.

Oil processing

The soaking of emerald crystals with (most often cedar) oil is a commonplace practice. When the deposits are developed, the found emerald crystals are lowered into canisters of oil to give them the density necessary for polishing. The colorless oil seeps into the crystal’s surface cracksL when the holes are filled in they are much less visible to the naked eye. To conclude this process, the now-polished rock is once again drenched in oil, which fills all the tiny remaining ravines. Such are the peculiarities of this mineral. Notably, if one were to clean their emerald with steam or ultrasound, the oil washes out and the cracks once again appear on its surface. In this case the rock should be once again drenched in oil.


Radiation refers to the process of bombardment of precious rocks with subatomic particles or radioactive isotopes. Interesting and lasting changes to the color happen during this process. Sometimes after the exposure the rock is subjected to a heat processing to attain a new color or a better old one. This created brightly and diversely colored diamonds, turmalin, topaz and other rocks. In the United States the bombardment of precious rocks is regulated by the U.S. Nuclear Regulatory commission for the exclusive use of radioactive minerals. This guarantee is not offered in any other country in the world.


It’s difficult to analyze whether painting is truly good or bad. More often than not painting is used for simple minerals. Chalcedony, or it’s better known agate variety, are often colored in a blue, green or orange color and used to prepare wonderful vases, statues and beads. Sometimes the painted goods look unnatural, though such unusual colors tend to attract buyers as well.

Soaking and stabilization

Soaking and stabilization are used predominantly for turquoise. The soaking presents the “pouring” of wax or paraffin into porous material, and the stabilization implies a connective substance, usually plastic, within the simple mineral. The soaked specimen cannot be exposed to heat, or else the rock might pour out of the small cracks and pores. The surface of some of the precious rocks is soaked with wax for the glint. The perks of this “stabilized” turquoise lies in the rock’s lack of absorption of foreign particles and the changing of color, unlike the unprocessed variant. Of course, to find unprocessed turquoise on jewelry store counters is practically impossible.


Whitening is used for organic-based rocks: corals, natural and artificially grown pearls. The process destroys the coloring elements and increases the rock’s stark whiteness.

Surface covering

Surface covering is the process of covering a rock with varnish or a thin layer of some other material to improve its appearance. This method is used sometimes to enrich diamonds, changing its surface and tricking the customers. You most likely won’t have to deal with such situations, but it’s best to stay aware. Opals are often covered in a thin layer of black film to enhance the color.

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