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»Snakeskin Agate«

natural »Snakeskin Agate«

Abb. 1: natural »Snakeskin Agate«

Foto: K. Sieber, www.makrogalerie.de

Since many years the trade name »Snakeskin Agate« applies for a beige chalcedony with characteristic white lines. (fig. 1).

In 2005, very similar looking material in bright orange colors appeared on mineral fairs, being sold by Chinese retailers as "Fire Agate". But this labelling is absolutely wrong and misleading.

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Singing bowls are very common in esoteric meditation circles. They usually consist of metal alloys which can produce a remarkably broad spectrum of tones through skillful processing.

The EPI laboratory received two unusual singing bowls for gemological testing. The importer declared that the bowls are produced from "cleaned Mountain Crystal". Similar descriptions are sometimes used for synthetic quartz or quartz glass. That's why both bowls were examined using X-ray diffraction (XRD) to determine if they contain any rock crystal or other crystallized products.

The analysis showed a curve typical for the diffuse reflection of artifical glass. Residues of crystalline quartz (rock crystal) were not found in the tested sample.

Therefore, the singing bowls have to be named as Quartz Glass. Since the Quartz Sand that was used for the bowls was completely smelted in production process, it is not allowed to include the term "rock crystal" in the product name. The naming "rock crystal singing bowl" is misleading.

 

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A green rock was submitted to the EPI laboratory, declared as 'Fluorine-Chrysoprase'. According to the rules of mineralogical nomenclature, 'Fluorine-Chrysoprase' should be a chalcedony containing nickel (= Chrysoprase) and fluorine.

Under the microscope the expected fibrous structure of a chalcedony did not show up. Pronounced cracks indicated a very very good cleavage. In addition the density of 2.9 - 3.1 did not fit on Chrysoprase. On a cut and polished surface the refracive index could be determined with 1.45, a value which can clearly be assigned to fluorite.

To determine the exact mineral composition and element content, a mineralogical thin section was made and an X-ray fluorescence analysis (XRF) was carried out. The thin section analysis clearly showed that apart from fluorite and the remains of decomposed feldspars, only coarsely crystallised quartz - but no chalcedony - was present. The element analysis (XRF) did not show a measurable content of nickel.

Fluorites in such a coarse formation as in the analysed rock are often very hydrous and are called Hydrofluorite.

According to these analysis results, the designation "Fluorine-chrysoprase" has to be classified as misleading. The correct name is (Hydro-) fluorite.

 

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Smoothly polished with a strong metallic lustere and magnetism strong enough to erase data on credit cards, a product called »Power Magnet« is sold on mineral faires since the beginning of the millenium. Children enjoy playing with the oval magnets for the incisive chirping noise created by tossing them in the air. But what is this highly magnetic material made of?

Some dealers suspected that the magnets may consist of sintered, neodymium doped Hematite. X-ray diffraction (XRD) analysis of a powdered sample carried out by the EPI laboratory revealed a different result: »Power Magnets« are manufactured from almost pure strontium ferrite mixed with some barium ferrite. Hematite or any other natural minerals have not been found.

Conclusion:

»Power Magnets« are a well known artificial sinter product used in many industry goods that require permanent magnets (e.g. fridge doors). The correct denomination is: Power Magnets (artificial product).

 

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Since the middle of the last century an Amber imitation has been on the market, produced by embedding real Amber chips into a transparent polyester resin. This imitation is called "Polybern". The name is derived from the contraction of "poly" from the word "polyester" and "bern" from the German "Bernstein" for Amber. For a long time this composition of fossil and synthetic resin had almost disappeared from the market, but now it is offered again in a slightly modified version. In this current product, transparent brown Amber chips are embedded into nontransparent white synthetic resin.