Myths and legends

How to distinguish real turquoise from artificial one?

Turquoise is a phosphate of aluminum and copper. Turquoise often contains microinclusions of other mineral phases – quartz, chalcedony, opal, carbonates, sulfides and clay minerals. Their presence deteriorates the quality of turquoise and makes it difficult to polish. The color of a mineral mainly depends on the deposit and the conditions of formation of the mineral. Some Uzbek deposits are characterized by the so-called “immature” turquoise – pale blue shades, almost white, porous and loose. If turquoise, during the process of its formation, is subjected to some natural chemical influences, or lies closer to the surface, it turns green. The color of turquoise and its main advantage is very diverse, varying from bright bluish blue, sky blue and greenish blue to pale blue. The blue color is due to copper, the greenish tints are due to impurities of iron oxide. The spotted color of turquoise, with black or brown veins, is very common. In the latter case, turquoise acquires a mesh or cobweb structure, which is called reticulate turquoise, also known as lace. On the surface of lace stones, dark veins are chaotically intertwined, forming a bizarre and beautiful abstract pattern. The hardness of the best jewelry samples on the Mohs scale is 5-6 g/cm 3 . For lower quality samples, the density ranges from 2,5 to 2,8 g/cm 3 . The rock is quite soft and can be scratched by glass or metal. When scratched, turquoise crumbles and does not produce shavings. A characteristic property of turquoise is microporosity, which sharply increases with weathering. Turquoise is susceptible to the action of various household substances – perfumes, oils, fats, chemical compounds, especially organic ones (gasoline, acetone). Turquoise deposits Turquoise deposits are usually found in regions with arid climates. The best turquoise in the world is mined from deposits in northern Iran, the USA (Arizona), Mexico and the Sinai Peninsula. The deposits of Mongolia, Afghanistan, China, Israel, Kazakhstan, and Uzbekistan are also considered rich. Turquoise deposits are rocky deserts with mountain ranges or various mountain ranges. The most ancient mines are considered to be the Nishapur deposits of Iran, deposits of Mexico and America. The development of these deposits lasted for 7-10 thousand years. It’s amazing that they still continue to be suppliers of turquoise. Imitation turquoise The highest demand for turquoise and rather expensive natural raw materials have led to an abundance of its imitations. Often there are fakes made of plastic, which melts when heated and smells bad. It is easily distinguished from turquoise by its much lower hardness and density. Fakes made by surface painting of special ceramics, porcelain, glass, bone, and cheap quartz are common. It is easy to check such a fake by cutting off the top painted layer. The so-called “Viennese turquoise” is marketed as turquoise – a heat-treated and pressed thin mixture of malachite with aluminum hydroxide and phosphoric acid. When imitations of turquoise are heated, they usually blacken or fuse into black glass rather than cracking like natural turquoise. In the 70s of the last century, a method was invented to synthesize turquoise industrially. As a result of this synthesis, it turns out to be very homogeneous, with evenly distributed, more intensely colored particles. Natural turquoise has a non-uniform color, the mesh pattern is uneven and imperfect. Some minerals have similar color and physical properties to turquoise and are used as its analogues. Examples include chrysocolla, variscite, amazonite, and lapis lazuli. How to distinguish a fake? It is very difficult to distinguish natural turquoise from a fake based on visual inspection alone. It is possible to identify a fake by the following signs: 1. if you drop hydrochloric acid on a sample and brown spots appear on it, this is an imitation (most likely “Viennese” or “Neolithic”). 2. You need to dip the stone in alcohol, and then wipe it with a napkin or a light handkerchief – if traces of paint remain, it is a fake. 3. Apply a hot steel needle to the sample: a brown mark will appear on the natural stone, and the plastic fake will begin to melt with the appearance of a characteristic odor. 4. try to scratch it with a metal needle or knife. The natural stone will be left with a groove of the same color as the sample itself. If the needle slips, bounces or becomes dull without leaving a mark on the specimen, if you try to scratch the sample, shavings appear or a groove turns out to be a different color from the “stone” itself – this is a fake. 5. Are bubbles or swellings visible in the structure of the stone under a magnifying glass? This is fake turquoise made from glass or earthenware. The plastic fake looks smooth and evenly colored, but feels very light to the touch. 6. The veins on pressed turquoise look like a pattern, the entire surface of the pressed stone is perfectly smooth, while on natural turquoise they are soft, it is clear that these are inclusions of a different breed. The surface is heterogeneous, uneven. Authenticity tests are recommended to be carried out on the back side of the stone, as there is a risk of damaging it. How to care for turquoise There are several rules for handling turquoise: – Do not clean jewelry with water, steam or ultrasound. – do not allow contact with active chemicals (for example, soap, household chemicals); always remove the rings when washing your hands. – to prevent the color of turquoise from fading and losing its saturation, protect it from sudden temperature changes, too dry air, excessively bright sunlight, contact with cosmetics or sweat, essential oils and other fatty substances. – after wearing, you should wipe the turquoise with a clean, soft, dry cloth. – store separately from other jewelry or in an individual bag so that the stone does not get scratched. – try not to subject the stone to strong blows or drop it from a great height. About the properties of turquoise Turquoise is recommended to be worn by those who suffer from chronic insomnia and severe nightmares; lithotherapists believe that it normalizes sleep and biorhythm. This stone is also useful for relieving headaches and diseases of the digestive tract. Turquoise has a beneficial effect on vision and the functioning of the endocrine system. People involved in singing are recommended to wear turquoise around the neck, this will protect the ligaments and smooth out the effect of colds. A small turquoise talisman will endow its owner with insight, set him up for self-knowledge, help him get rid of unnecessary fuss, and protect him from ill-wishers. It is generally accepted that the mineral, having strong energy, nourishes its owner. +7 (499) 34-34-796
Exhibition address: Moscow, st. Krasnoproletarskaya 36
Two Giraffes E-mail: dvajirafa@yandex.ru Today we have a wonderful “turquoise” week! And there have already been publications about turquoise, but I would like to share with you some practical aspects of knowing this amazing stone. So, many jewelry makers have probably thought more than once about the issue of the naturalness of the materials they purchase for their work. And often, unfortunately, the conclusion is not in favor of naturalness. Alas! But, as we know, he who is informed is armed. So I suggest arming yourself with knowledge. Modern fakes and imitations of turquoise are very artistic, and there are a large number of them. Natural turquoise differs from minerals and other materials that imitate it in physical properties (hardness, density, color, luminescence, waxy luster, etc.). Under a microscope, the surface structure of natural turquoise has a characteristic appearance: dark blue disks or whitish fragments and inclusions are observed against a light blue background. In synthetic turquoise, at high enough magnification, angular blue particles are observed against a lighter background. The absorption line characteristic of natural turquoise is absent in the absorption spectra of synthetic turquoise and imitations. The hot needle test can reveal refined turquoise: where the hot needle touches, paraffin melts or the stone becomes discolored. Plastics and resins melt from the hot needle.
Synthetic turquoise differs from natural texture (under a microscope) and a different nature of interaction with dilute HCl. Since turquoise is characterized by a fairly wide range of physical properties, it is identified by a comprehensive study using X-ray, spectral (in the IR and visible regions) methods and electron microscopy (lamellar-prismatic microcrystals are observed). Today, artificial turquoise is used most often for jewelry. It is made from copper aluminophosphates, colored synthetic plastics and ceramic materials with coloring additives (sometimes natural turquoise waste is used as additives), and also imitates chrysocolla, variscite and blue-dyed howlite. The situation is especially difficult (with regard to determining imitation and counterfeiting) with turquoise, since it is counterfeited not only by surface coloring of plastics and gypsum, but also by coloring similar minerals, for example howlite and various quartz. Now they have even learned how to create synthetic turquoise, which is very similar in composition to natural one, and even experienced gemologists cannot accurately identify it.
So, first, you need to carefully examine the holes (turquoise is porous): if the material inside the hole is white, it is a fake.
You can rub the stone with a damp cloth and see if the paint remains on the fabric, but this is not very reliable – the dye may be strong. Or try rubbing thoroughly with a cotton swab soaked in alcohol. If the stone is painted, the fleece will get dirty. But this method reveals only superficial cheap paintwork.
You can hold turquoise over a match: if it turns black and melts, if a characteristic plastic smell appears, then it is plastic disguised as turquoise. All actions must be carried out on the back side of the stone, since the check usually leads to damage to the stone.
Try scratching the turquoise with a needle. If the stone is not scratched, but the needle rubs off on it, then you are most likely looking at an imitation made of faience, glass or chalcedony (when the hardness of the stone is more than 5,5 according to Mohs, turquoise cannot have this).
If turquoise scratches too easily, with shavings or white powder – it’s plastic. The white stripes under the top colored layer are also questionable, since natural turquoise is colored throughout its entire depth.

Heat the needle and touch the stone.
On treated turquoise (dyed, impregnated with resins or wax), the color will change at the point of contact or a drop of impregnation will appear. Plastic imitations will begin to melt with a characteristic smell of burnt plastic. Odontolitis emits a burnt bone smell.
A good criterion for the “naturalness and authenticity” of turquoise is its size and price. A size of more than half a centimeter is already quite large inserts, they indicate that this is either a pressed crumb or an imitation. Remember that natural jewelry turquoise is a rare and expensive mineral; moreover, it is found in nature only in small pieces; it is unlikely that it will be used to make beads or earrings.
The price of a product, even with a small insert of natural turquoise, starts at an average of $200; anything cheaper is not turquoise! Real turquoise is quite expensive. And it is very difficult to buy it because of its rarity: almost everything that is sold in stores is an imitation, with rare exceptions.
As already mentioned, bones or teeth of fossil animals can also serve as a substitute for turquoise. They are colored with iron or copper salts. When dyed with iron, the color turns out to be blue, and green will appear if dyed with copper. Such bones are well cut, polished, and products made from them are often sold as turquoise. So, if you see such an incomprehensible name – bone turquoise, or western turquoise, rest assured that this has little to do with natural turquoise.
Today there are many natural stones sold under the guise of turquoise. The most commonly offered are chalcosiderite, aluminochalcosiderite, raschleite, fostite (faustite), vardite, variscite, chrysocolla, dontolite, stellarite, etc. Many of them are inferior in quality to turquoise. Often offered from the USA, quartz and colored chalcedony are clearer and have a lower density. Imitation made from natural stones is the best imitation of turquoise.
Some of the “analogue backups” have good characteristics. For example, turquenite (the trade name for colored howlite) is a very worthy substitute for turquoise (its deposits are greatly depleted); in some characteristics it surpasses even refined turquoise. It does not crack when heated, does not change color, and is not afraid of water and light. In essence, turquenite differs from turquoise only in its porcelain shine (as opposed to the waxy or silky shine characteristic of natural turquoise).
Variscite and lazulite
Variscite and lazulite are minerals similar to turquoise; They are both hydrous aluminum phosphates but do not contain copper. The density of lazulite is 3,1 g/cm3 (more than that of turquoise), hardness – 5,5, refractive index 1,61 – 1,64. Lazulite is sometimes called “bluespar.” Unlike cryptocrystalline turquoise, it is represented by a fine-grained material.
Variscite has a density of about 2,4, a hardness of 4–5, and a refractive index of up to 1,57. Color: green, dark green, blue, yellow. Glass shine. Forms crusts, nodules, and rarely octahedral crystals. There is no cleavage. The most common varieties of variscite develop in the form of eyes, which is not typical for turquoise.
High quality variscite is as rare as good turquoise, if not rarer.
Colored minerals:
Colored howlite is silicoborocalcite, lighter and softer than turquoise. The color of the painted material can be very bright, its price is much lower.
Dyed quartz and chalcedony are materials that are significantly cheaper than turquoise and are offered by American suppliers. These stones are more transparent than turquoise, lighter (density 2,63 g/cm3), with a lower refractive index – 1,53 and greater hardness (6,5 – 7). All colored minerals can be distinguished from natural turquoise by their weight. Natural porous turquoise is distinguished by its amazing lightness. Organic compounds. Odontolitis. In the past, turquoise was often passed off as odontolite—fossil ivory, fossilized teeth, or fossil animal bones partially replaced by iron or copper phosphates and colored blue or green. Externally, the material is very similar to turquoise. The refractive index of odontolite is 1,57 – 1,63. Hardness 5. Density above 3 g/cm3. Boils from hydrochloric acid. The primary organic structure of the mineral is visible in thin sections.

A reliable way to separate turquoise from ornamental materials of organic origin is the ability of organic matter to burn.
Artificial minerals and materials:
Successful counterfeits are obtained by pressing a precipitate of aluminum phosphate, colored blue with copper oleate, as it has almost the same appearance, hardness and density as turquoise. Unlike natural stone, artificial material melts in the flame of a blowpipe.
“Vienna turquoise” is an imitation obtained by joint crushing, heating (more than 100°C) and pressing a mixture of malachite, aluminum hydroxide and phosphoric acid. The formula of this material is different from turquoise. The hardness of pressed turquoise is about 5. Density is 2,4, when saturated with water it increases to 2,6 g/cm3. Refractive index 1,45. When heated, this fake blackens or fuses into black glass rather than cracking like turquoise.
“Synthetic turquoise” (Neolithic) – distributed since 1957. The stone has a pleasant blue color, sometimes with sinuous veins of the “ground mass”. It is a mixture of bayerite and copper phosphate, and the bulk is an amorphous iron compound. Bayerite is a by-product of aluminum production, similar in composition to hydrargillite. Hardness about 4. Refractive index 1,55. Density 2,4 g/cm3. Almost Neolithic is identical to Viennese turquoise.
Artificial turquoise, consisting of small grains of blue and white material cemented with alkyd resin, was created in 1953 in America. The hardness of this turquoise is about 2,5. Density 1,85 g/cm3. In some samples, the hardness reaches 3,5 and the density 2,39 g/cm3.
Glass and enamel – were first used as imitations by the Egyptians 5 thousand years BC. e. to obtain a material similar to turquoise. Blue glass beads were found in the tomb of Tutankhamun (1350 BC), they were colored with cobalt. Modern glass beads are also made to look turquoise. Enamels that imitate turquoise are slightly discolored silicate glass mixed with a mixture of metal oxides. Most glass imitations have a higher density compared to natural turquoise. A doublet made of chalcedony and glass is also often passed off as turquoise.
Plastic is, of course, the cheapest imitation of turquoise. Cabochons are cast from it, sometimes with a cobweb pattern characteristic of turquoise. But the coloring of plastic products is too perfect. They are lighter, softer, non-porous and without the characteristic waxy sheen; on the contrary, they have a glossy shine. When using colloidal silica as a binding mass, the density of the resulting material is 2,65. If you look from a magical point of view, then mystical properties are characteristic only of imitations of turquoise in natural stone. However, a painted stone retains only its own properties; it does not acquire the properties of turquoise. I would like to add that no one has canceled honesty and urge sellers of materials to give as truthful a description of a particular stone as possible, even if these are obvious things to you. At the beginning of my career, I encountered an unpleasant situation when, out of ignorance, I bought an opalite pendant (however, quite a beautiful pendant!), believing that it was a natural adularia (moonstone). I had reason to believe so, since this pendant was in the “natural stones” section and was called precisely “moonstone”. When I figured it out and turned to the seller (with a request for clarification), I heard something like the following in response: “Didn’t you know? Yes, this is the trade name of opalite!” Yes, at that time I didn’t know, but the trade name itself cannot deceive, and it is the person, the seller, who is misleading, who knows, but for some reason does not explain to naive citizens that this is an imitation. I am sure that I have not discovered anything new for experienced craftsmen, but I will be glad if the material turns out to be useful to someone! Based on the article: “How to distinguish natural turquoise from imitation?” Thank you for your attention, best regards, Anna.

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button