CAT EYE - CHRYSOBERILL

Characteristics of the mineral.

A variety of chrysoberyl BeAl2O4. It is rare in nature. Jewelry varieties include beryl, ruby ​​and sapphire cat's eye. Almost invariably part of the aluminum is replaced by oxide iron and chromium, and some of the beryllium is replaced by ferrous iron. Sometimes there is titanium. Various shades of coloration of chrysoberyl (yellow - iron oxide, green - chromium, reddish - titanium oxide) are due to these minor impurities. The most common pale yellowish chrysoberyl owes its color to the presence of iron, and chromium causes a greenish color.

Chrysoberyl belongs to the number of precious stones, known since ancient times. Golden-yellow with a bluish outflow of chrysoberyl is called cymophane. Huge popularity was enjoyed by cymophanes (golden yellow and greenish-yellow chrysoberyls) with the effect of a cat's eye. One of the varieties of chrysoberyl - alexandrite has a green color in daylight and violet-red with electric (incandescent). The stones with the effect of the cat's eye are traditionally cabochons. In Sri Lanka was discovered the largest chrysoberyl cat's eye mass of 475 carats.

The main supplier of this precious mineral is Brazil, where it is extracted from alluvial placers together with tourmaline, topaz, garnet, etc. The second most important place in the extraction of chrysoberyl is Sri Lanka, where precious stones are extracted from the pebbles in the south of the country. Chrysoberyl here is represented by varieties of yellow and green, cat's eye and alexandrite. In recent years, chrysoberyls, especially alexandrites and cat's eyes, are very rare and cost fabulously expensive. The main areas of production of cymophane are placers of Sri Lanka and Madagascar.

The chrysoberyls shown on the photo are very expensive (hundreds and thousands of dollars per carat in jewelry), although they are somewhat gloomy in appearance in the sunlight and practically lose their color under artificial lighting or in the evening. It was these stones that were called widows.

Chrysoberyl is a precious stone that once enjoyed tremendous popularity due to the fact that the turbidity stones give an excellent "cat's eye" effect. If the composition of chrysoberyl exactly corresponds to its chemical formula, it is pure and colorless. In some cases, crystals of chrysoberyl contain numerous microscopic tubules or fibrous inclusions that are parallel to the crystallographic axis. Since the tubules in the chrysoberyl are usually hollow, opalescence appears. The effect also arises from microscopic fine-fiber inclusions (for example, actinolite or asbestos). When processing such a stone in the form of a cabochon, a wide silver-white strip of light appears, which in the form of a playing ray dissects it in two and creates the effect of a cat's eye.

Most of the stones on sale with the name "cat's eye" are synthetic ulexites or fakes of glass, since natural stone is expensive. Today, synthetic imitations of bright green or yellowish color from the composite material with tubules-voids, issued for natural chrysoberyl, appeared on the market. Its production is presumably established in China and the USA (a product of high optical fiber technologies - sintering at high temperature with the addition of a dye of glass optical fibers). The material is called a ketzite.

Synthetic and fake cat eyes

IMITATION. Most imitations today are made of glass of different quality with various additives (Savrovsky stones, glass rhinestones, black and gold aventurine, milk moonstone, green chrysoberyl, opal glass, etc.). This includes the cat's eye.

All that is mass sold in stores - imitation and fake in the glass (imitation is easy to get from cheap fibrous borosilicate glass). Simulation of glass can have any size and colors and very bright glare. Cat's eye glass is the most common and inexpensive fake and imitation. It is often sold in the form of beads and bracelets with a very pronounced effect of the eye and glare. Synthetic cat's eye is of any color: whitish, green or blue, red, pink, yellow, brown, etc. It is very bright and has a pronounced phenomenon of iris (a bright noticeable glare running along the surface during rotation). Do not confuse the cat's eyes with asterix stones, on the surface of which the star runs at the rotation, and not a wide band.

SYNTHETIC CAT EYE. I want to pay special attention to the photo on the right. Today in the market there were synthetic imitations of bright green or yellowish color from the composite material, issued for natural chrysoberyl. Its production was presumably established in China on the basis of a special optical glass with coloring additives. The technology was developed in the USA. It is made of rare-earth silicates, compressed in the form of a mass of narrow parallel fibers, having a diameter in diameter from 6 to 10 microns. They are fused with a colored matrix with lower refractive indices of light. The material is called ketsite ("cat's eye area"). Small samples can shine through, large opaque. One cubic centimeter of the material contains fibers, the total length of which exceeds 8 kilometers !! It is a by-product of development and development of modern fiber-optic technologies. Under the guise of natural chrysoberyl, decorations from ketsayta are sold even in specialized departments and shops, at exhibitions and "with hands" or trays at a price of about 50-150 dollars and higher for allegedly a jewelry product. This is a fake and fraud (you can apply to the police). If in the market you will get such beautiful bright green or yellowish beads with micro-canals and a specific iris for 5-20 dollars. (As though they were not called), you will not lose - this is the real and real price of an extremely curious man-made material. By the way, abroad this material is much more expensive than in Ukraine, but still at a price not comparable to chrysoberyl. Theoretically, colors such as green, honey-yellow, blue, pinkish, white are possible. Think about that, unlike ketsait, a natural chrysoberyl cat's eye costs as much as a diamond of a similar size or even more expensive.