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The GERMAN INSTITUTE OF GEM EXAMINATION (EPI) is a guarantee for the reliable determination of the identity and the state of treatment of gemstones and precious stones.

  • In the section INFORMATION you will find news about treatment methods, imitations & fakes, current research results on gemstones and precious stones.
  • In the section TOPICS information about gemstones, treatment methods and their potential risks are listed.
  • A preview of our written documents and an actual  price list you will find in the section SERVICES

 

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The EPI team

 

 

Category: Topics

Statues made of nephrite jade can weigh several tons.

© K. Sieber, www.makrogalerie.de

 

In China, the term "jade" has been used for at least 5000 years. Because of its very special nature of being tough and resistant like no other material known at that time, "jade" was used not only in Asia, but also in Europe and America for the production of tools and weapons. Over time, the material was also discovered for art objects (vases, sculptures).  A veritable "jade" cult began to develop, especially in China..

Category: Imitations

Artifical product "Andara Crystal" (bottle glass)

Foto: K. Sieber, www.makrogalerie.de

 

The term "Crystal" is used for both: natural grown crystals as well as artificial glass. The use of the term "crystal" for not crystalised products is kind of missleading and prohibited in European countries.

Companys like Swarovski make use of this misleading linguistic extensively. For marketing reasons, Swarovski avoids the word "glass" whenever possible and rather speaks of »Swarovski Crystal«. However, especially when dealing with jewelry this creates a considerable risk of mistaking them for natural products. That is why the practice of Swarovski and other artificial glass produducers is to be refrained from.

The risk for mistaking artificial glass for a natural product multiplies significantly in the case of Andara Crystal by selling raw and tumbled stones "from natural deposits". The producers provide pictures of raw stones of several foot in diameter on the Internet with the intent of suggesting natural occurency.

Category: Lookalikes

Compared to the widespread, well-crystallized, transparent representatives of its kind, coarse fluorite is a little noticed mineral. Its relatively inconspicuous and "atypical" appearance, often leads to confusion with other minerals.

Many of these derby fluorites are very hydrous and are therefore called Hydro-Fluorite. (Hydro-) Fluorite (CaF2 x H2O) has a hardness of 4 on the Mohs scale and a density of 3.1 - 3.3. The most common variety commes in purple color.

Hydrofluorite as »Lavender Jade« Imitation

Hydrofluorite as »Lavender Jade« Imitation

Hydrofluorite as »Lavender Jade« Imitation

Foto: EPI

Category: Lookalikes
Epidot-Zoisit Gruppe

Fig. 1: Chemical composition of some minerals from the epidote-zoisite group

Grafic: © EPI-Institut

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The mineral zoisite is a calcium (Ca) - aluminum (Al) silicate with the formula Ca2Al3[O|OH|SiO4|Si2O7]. It is capable to form single large crystals, but also massive rock bodies. By incorporation of the element manganese (Mn) into the crystal lattice, zoisite gets a pink to brown-red color (trade name: »Thulite«). Chromium Turns tho color of the mineral into green (trade name: »Anyolite«) and vanadium into blue (trade name: »Tanzanite«). Zoisite forms crystal shapes with orthorhombic symmetry.