Slightly scratches blue topaz

Counterfeit Gemstones and Minerals



Some gemstones and minerals that are commercially available are not always as natural as one might think.



Even in Cleopatra's time in ancient Egypt, it was common practice to artificially color simple glass and act as valuable stones.

Over time, the developed techniques for forgery, synthesis and imitation of precious stones became more and more sophisticated, so that today fake stones are very similar to the real, natural model and can hardly be distinguished from one another.

For lovers or hobby collectors of minerals and gemstones, this is of course a big annoyance if there is a lack of specialist knowledge.



False gemstones and minerals are differentiated into syntheses and imitations based on the type of production.




Artificial crystals

The first synthetically manufactured gemstones came up at the beginning of the 20th century.
Initially, the synthesis of gemstones focused on scientific interest. At that time, no one thought of commercial exploitation, as the gemstones from the laboratory could not be used for jewelry anyway due to their small size.

The French chemist Auguste Verneuil then developed a process that is still used today, with which larger crystals can be produced.
The basis of the so-called Verneuil gemstones are oxides in the form of powders to which color-giving additives are added. At temperatures around 2,000 ° C, the mixture is fused together in an electric furnace. The liquid mineral melt is then directed onto a base around which the "liquid mineral" cools, solidifies and hardens. The result is a coarse, pear-shaped mass, the melting pear - but without the crystals characteristic of minerals.
In nature, centuries can sometimes pass before a mineral is formed. In comparison, with mineral syntheses, the crystalline result is already in your hand after about three to four hours.
In the beginning only rubies were made in this way. You can even imitate the star effect (asterism) typical of the star ruby ​​with a 6-pointed star.
Sapphires followed later - in 1910.

Little by little, every imaginable color scheme was figured out and imitated in the laboratory, even the production of colorless corundum, so-called diamondites, was possible. In 1947 the first emerald syntheses came onto the market. Above all, a company from Bitterfeld in Saxony-Anhalt made a name for itself as a manufacturer of synthetic emeralds. The I.G. The artificial emeralds produced by Farben Bitterfeld ** were sold as Igmerald. Igmerald is made up of both the company name I.G. Colors and the ending of the English word for emerald emerald together.

The imagination of the gemstone makers was and is no limit. In the course of many experiments with colors, gemstones were created that were not based on nature, such as fabulite or diagem (strontium titanate), djevalith (zirconium calcium zirconium oxide), galliant (gallium gadolinum garnet) and YAG or Diamonary (Diamonair-Yttrium-Alluminate).



Recognize and differentiate between real and fake minerals

Due to the fact that syntheses have similar physical properties to real minerals - namely gloss, hardness, transparency, cleavage and breakage as well as color, these must be identified as such when purchasing.
Complete certainty as to whether a gemstone is actually a synthesis can be obtained by looking into a microscope. Inclusions, artificial growth structures or superficial scratches, which for example do not occur with some minerals due to the Mohs hardness, become clear.
Last but not least, artificial crystals also differ in terms of their chemical composition from the replicas from the laboratory. Investigations of minerals and forgeries in spectrometers provide information about the chemical components of the stones using atomic absorption spectrometry and can unmask imitations and syntheses.

Counterfeit gemstones

Counterfeit gemstones are made up of either composite stones or imitations.

At composite stones Minerals or rocks of small size experience an increase in size and value by being melted or pressed together with other materials.
One example of this is pressed amber, which has been traded since 1880. Lapis lazuli is imitated by fused blue glass and shiny metal particles that are supposed to imitate the pyrite naturally occurring in the rock. On the other hand, fine mineral splinters are used for composite stones, which are glued to glass substrates. This creates the impression of an imposing gemstone with a top-class weight.

The variations of the artificial stones are great, depending on whether a colored layer, mostly colored foil is used, is placed between a colorless top and bottom or the lower part consists of colored glass. In some cases, these illusions are so perfected that it is difficult to distinguish them from real gemstones; especially since these products are often already set in jewelry and the possibly visible connection points or seams are covered by claws or the setting.

Imitations of precious stones and minerals consist essentially of glass, resin or plastic, to which color is added - depending on which "artificial mineral" is to be created.
Imitations are easy to transfer, because apart from the color, there are no other characteristics in common with the original from nature.

The most famous imitation of diamond is strass. The shiny piece was named after the inventor Joseph Strasser, who in 1758 succeeded in melting glass together in such a way that it was of a quality worth grinding like a diamond. Alternative names for rhinestones in stores are Rheinstein, Rhinestone or Simili.

Zirconias are to be distinguished from rhinestones. From a chemical point of view, zirconia are artificial zirconium dioxide crystals from the laboratory - in comparison, glass or rhinestones are made of silicon dioxide.

In addition, minerals are reproduced using porcelain or ceramics. Larimar fakes in particular are made of colored porcelain.

Last but not least, imitation gemstones are also a question of price and can be identified simply because of the price, which is often only a fraction of real gemstones in comparison.

Changes in color of natural gemstones

In some cases, however, natural gemstones and minerals are also changed. There are minerals that have an uneven color distribution, are too pale or too dark. By firing - the mineral is heated to temperatures of 300 to 600 ° C - alleged errors can be repaired, corrected or completely changed in color as a result of the supply of heat. In this way, for example, yellow citrine is created from purple amethyst, and blue zircon or diamond is simulated from brownish hyacinth.

It is also possible to influence and change the color of minerals by bombarding them with radioactive or X-ray radiation. However, due to the decay of the "bombarded" atoms, the colors are not permanent and only last for a short time. As a result, the color changing effect is not permanent. One mineral that the process applies to is blue topaz. Above all, yellow or colorless topaz, which is not sold on the gemstone market and whose color is too weak, is colored into the coveted topaz blue with ionizing radiation or heat. Depending on the intensity of the treatment, three different colors are created: Swiss Blue Topas, Sky Blue Topas and London Blue Topas.

And most of the brightly colored agates in blue, pink or purple do not occur naturally in this way. In this case, the porosity of the mineral is used to inoculate it with dyes and to obtain agates the color of the rainbow.

Minerals that have been changed in color by firing and inoculating can sometimes irritate the buyer, as they do not have to be identified and so the impression can arise that they are natural specimens.


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See also:
⇒ Trade names of minerals and mineral syntheses
⇒ Larimar forgeries
⇒ Diamonds that aren't
⇒ Amethysts - forgeries, imitations and syntheses
⇒ Rubies that aren't - fake rubies
⇒ Sapphires that aren't - fake sapphires



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Last updated: October 28, 2020

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