Vera PAKHOMOVA, (c)
by Vera PAKHOMOVA, Cand. Sc. (Geol. & Mineral), leading research assistant of the Laboratory of Minerageny of the Far Eastern Geological Institute of the Far Eastern Branch of the Russian Academy of Sciences, state expert in mineralogy of the Primorski Department of the RF Ministry of Culture (Vladivostok)
Semiprecious stones are a wonderful creation of nature, which did not grudge colors for their creation. Let's recall the words of the well-known scientist and promoter of aesthetics of the mineral world Academician Alexander Fersman: "The future of semiprecious stones is not in their value or wealth but in their beauty, harmony of colors and forms and their eternity". Gemology (from Latin gemma—a precious stone, Greek logos—teaching) helps feel deeply this harmony and beauty. This sphere of science studies minerals and their aggregates used in different branches of engineering and technologies, in jewelry and building industries, and also in everyday life of people. The economic reforms of the 1990s resulted in a rapid growth of the national gemological industry and creation in our country of specialized scientific, educational and expert centers. The considerable part is found in Siberia and the Far East, where a high potential of hard mineral deposits with semiprecious stone mineralization is concentrated.
FORMATION OF A BRANCH OF SCIENCE
Archeologists ascertained that cultural development of people (counted since the 1st century A.D.) started surprisingly from manufacture of beads. They were found during excavations of ancient dwelling sites together with stone implements used by primitive tribes to get daily food and also to process jewelry pieces. These small artifacts with holes are considered by right to be elements of the first jewelry created by man and information obtained in the course of their manufacture to be the first bricks laid in the foundation of future science.
It is customary to connect the onset of gemology (the first stage of its development) with empirical accumulation of knowledge in the process of stone usage in various spheres of human activity such as ore mining, construction, different crafts and technologies, spiritual culture, religion, science and arts. In the 18th century, when diagnostics of jewelry stone acquired a value of exact knowledge, there started the second stage, which ended at the turn of the 19th and 20th centuries. Just then gemology was finally separated from another geological science, i.e. mineralogy.
The review of scientific achievements in this sphere should be started from attempts to synthesize precious stones. In 1837, the French chemist Marc Godin managed to grow several small ruby crystals by combined melting of potassium alums and potassium chromate. In 1851 Ferdinand Zirkel (Germany) invented a polarization microscope, which caused a revolution in many branches of natural sciences, and semiprecious stones became an object of studies by special spheres of geology, i.e. petrography, crystallography and mineralogy. In 1866 the first scientific paper on semiprecious stones was published by the British gemologist Arthur Church in the Intellectual Review journal on the discovery of absorption lines in the spectra of Ceylon sapphires and almandines. Besides, development of special instruments was initiated by his countryman Herbert Smith, who created a refractometer for measuring of refractive indices of precious stones in 1906.
Nevertheless, the very term "gemology" appeared in the press only in 1892. But only 16 years later, in 1908, the first gemological association was established in Great Britain. From 1910, there began functioning training courses for appropriate specialists in this country.
The indispensable contribution to this science formation was made also by the Gemological Institute of America founded in 1931 by Robert Shipley (Los Angeles, USA), the Mechanical Laboratory in London (Great Britain), the Institute of Precious Stone Research in Mainz (Germany), the Laboratory of Diamond Research in Johannesburg (Republic of South Africa). Later large profile centers appeared in Italy, Japan, Thailand and some other countries. Research work and training of gemologists in the majority of countries are conducted within a framework of national associations
and societies. The present-day European Federation of Gemological Education acts on the basis of 12 leading institutes from Austria, Great Britain, Germany, Belgium, France, Italy, Holland and Spain.
Over a period of more than 30 years international gemological conferences are held one in two years. Periodical publications promote spread of scientific achievements in this field.
The scientific basis of national gemology was laid before the Russian Revolution of 1917 by the well-known mineralogist Academician Alexander Fersman (1883-1945). He wrote the fundamental work Studies in Stone History (posthumous edition of 1953) and also several popular books such as Precious and Colored Stones of Russia (1920), Semiprecious Stones of Russia (1921), Entertaining Mineralogy (1928), Reminiscences About the Stone (1940). According to his students, Fersman strived to penetrate into "the heart of gems". Ideal crystals or well-faceted precious stones awoke in him a complex association of thoughts and emotions. They imply the romance of Oriental legends of magic properties of minerals mixed with geochemical ideas of their formation and thoughts of possible utilization in engineering. Fersman was an ardent supporter of launching production of semiprecious stones and jewelry raw materials in the country and one of the promoters of the State trust Russkiye Samotsvety (Russian Semiprecious Stones) in 1922. Based on the classification of the German mineralogist Max Bauer he developed the first national systematization of precious and colored stones in 1925.
Fersman trained a number of talented people, including professor Vladimir Kryzhanovsky (1881-1947), Georgi Lemmlein (1901-1962) and Georgi Barsanov (1907-1991), both Drs. Sc. (Geol. & Mineral.). Modern gemology is indebted to these great scientists and also to the experience accumulated by their followers such as academicians Yevgeny Kievlenko and Dmitry Rund-kvist, Vladimir Bukanov, Cand. Sc. (Geol. & Mineral.) and other outstanding specialists.
In recent years the science of semiprecious stones is intensively developing as it was enriched with new sophisticated research methods such as X-ray diffraction, adsorption optical spectroscopy, Raman effect and electron microscopy. Despite its tender age, this science managed to win strong positions in the country due to creation of basic methods of prospecting for deposits of colored stones, development of theoretical principles of prognostic and mineragenic studies and substantiation of a new research trend, minerageny (from Latin minera as ore and Greek geneia as origin, creation), which studies regional geological regularities of formation and location of various mineral deposits.
But basic regulations of gemological trend in classical geology are only being developed. As in case of ore formation delineation, there are complications and contradictions in approaches to classification features during definition and delineation of semiprecious stone forma-
tions. Differentiation and spatial-time specificity of minerageny of semiprecious stones in individual regions of the world and peculiarities of structural and material complexes are determined by a diversity of conditions over a period of geological history of the Earth. The paramount task of gemology is to reveal provinces of semiprecious stones of a certain paragenesis* as independent mineragenic and tectonic structures in interac-
* The term "paragenesis of minerals" was suggested by the German chemist Johann Breithaupt in 1849, though in 1798 this concept called "adjacency of minerals" was introduced by Academician Vasily Severgin. It became most widespread in the 1920s in the works by Academician Vladimir Vernadsky. Minerals, which form paragenetic associations, occur as a result of development of any natural process taking place in time periods different in duration and also in various physicochemical and thermodynamic conditions.—Ed.
tion with rock composition and characteristics of petrology and geochemistry.
Starting from the second half of the 20th century, after the Yakutsk diamond-bearing province was discovered in the basin of the upper stream of the Vilyui river (Western Yakutia) in 1954, our country became a major producer and exporter of precious stones. This necessitated revision of the attitude of the state to the industry and organization of diamond cutting to jewels in our country. In the 1960-1970s, jewelry factories were constructed under common design in Smolensk (the biggest in Europe), Moscow, Barnaul, Gomel, Kiev, Vinnitsa and Norachen near Yerevan.
A new stage in studies, prospecting and use of semiprecious stones started in 1966. Due to efforts of large teams of geologists from the territorial production associations and specialized surveying companies of the Ail-Union Industrial Association Soyuzkvartzsamots-vety, more than 100 deposits of amber, emerald, alexandrite, spinel, clinohumite, scapolite, turquoise, deman-toid, chrysolite, chrome-diopside, amethyst, lazurite, nephrite, charoit and jadeite were discovered. But despite a rapid industrial growth of the gemological industry, the Commission for Semiprecious Stone Raw Materials attached to the All-Union Mineralogical Society of the USSR Academy of Sciences was set up only in 1978.
The economic reforms of the end of the 1980s promoted integration of the country with the world market and growth of private enterprise including in the jewelry sphere. In this context, demand for gemologists rose sharply, who were sought after in many spheres of private and public business.
The first profile training of specialists was started in the country at the Moscow Geological Prospecting Institute named after S. Ordzhonikidze, where students of the department of mineralogy studied grading of rough diamonds. Here in 1995, the non-profit educational institution Gemological Institute was established (headed by professor Yuliy Solodov), which trained experts in jewelry. In 1996 the institute accommodated the Russian branch of the Gemological Institute of America. In those days the Lomonosov Moscow State University introduced special subjects in the training program.
Moreover, the profile scientific, educational and expert centers were established, apart from Moscow, in St. Petersburg, Yekaterinburg, Novosibirsk, Tomsk, Krasnoyarsk and Irkutsk. At present in these cities higher educational institutions of the natural science profile have special chairs, which provide full-fledged gemological education. The Novosibirsk State University opened a magistracy in gemology, while in Tomsk this subject is taught within the framework of a specialty "Mineralogy, Geochemistry and Petrology" since 1994. Here in 1995 an independent gemological commission of experts was set up and registered. Scientific conferences held since 2003 have become an undoubted achievement of the Tomsk school. The regular sixth conference will be held next November at the Tomsk State University based on the chair of mineralogy, geochemistry and the Mineralogical Museum. It is pleasing to note that a special priority will be given not only to general and applied gemology but also to mineralogy and geology of deposits of gems and rare raw materials, problems of synthesis and ennobling of precious stones, specialist training and cultural activities.
Since 1992 in Krasnoyarsk, a major scientific center of Central and Eastern Siberia, the Gemma company is, one
of the first non-government institutions in this territory. It was granted a license for expert, evaluation and educational activities. Irkutsk, the fifth in size city in Siberia, keeps pace with its neighbors and is noted for the achievements of the well-known gemologists in this country and abroad Boris Shmakin and Viktor Zagorsky, both Drs. Sc. (Geol. & Mineral.) from the Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences and Raisa Lobatskaya. The latter promoted creation in 1995 of the chair of gemological diagnostics at the Irkutsk State Technical University, which was later granted a license for training of specialists in the "Technology of artistic processing of materials".
INNOVATIVE TECHNOLOGIES OF SIBERIAN SCIENTISTS
Today the demand for high-quality synthetic jewelry as analogs of natural gems increased considerably in the world. But its structure changed radically. While several years ago about 70 percent of synthetic stones were used for technical needs and 30 percent in the jewelry sector, today this ratio is quite the opposite, i.e. the latter reaches almost 70 percent. It is explained by equalization of price and net cost for synthetic stones and natural technical raw materials, decision of the leading laboratories such as the Gemological Institute of America to accept synthesized cut diamonds for certification and, finally, by development of technologies ensuring upgrading of cultured crystals and optimization of color solutions.
Novosibirsk became one of the recognized centers of synthesis of jewelry stones in our country. The Institute of Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences (today the Institute of Mineralogy and Petrography) developed technologies and industrial production of synthetic uncut diamonds, emeralds grown by hydrothermal and flux methods, red magnesium spinel, high-quality Siberian alexandrites, noble opals and others.
Certain types of synthetic jewelry stones of this manufacturer have been recognized as best in the world.
The New Diamonds of Siberia scientific-production company, whose research activity is concentrated in Novosibirsk Akademgorodok and jewelry production in Krasnoyarsk, demonstrates results of the world level. In 2003 its specialists developed and patented a technology
of ennobling of natural diamonds of an initial brown color to a final pink-red with shades. The commercial production of such minerals started here in 2004 and entered the world market under the Imperial Red trademark. The company produces, apart from diamonds of red color, cultured cut diamonds of yellow-green fancy colors and also colorless and light-pink stones using the "classical" high-pressure annealing method.
Nowadays the Siberian scientists are engaged in production of monocrystals of synthetic diamond using the high-pressure apparatus BARS. This growing process will provide perfect monocrystals of a very hard mineral of more than 10 carat size with the given set of impurities and intrinsic defects for application in modern microelectronics, scientific instrument-making and a single-point diamond tool.
FAR-EASTERN GEMS AND THEIR STUDIES
Primorski Krai is actively developing the jewelry industry. In this context, it can compete even with Yakutia, which is a monopolist of the uncut and cut diamond complex of Russia. It is not incidental that it is here that a gemological laboratory, unique and the only one in the region, has been setup as a part of the Far-Eastern Geological Institute. The idea of its creation appeared in the mid-1990s when a group of scientists headed by Boris Zalishchak developed diagnostic methods of gems, and its members got diplomas of gemology experts. It helped form a laboratory of the required profile.
Its skilled specialists equipped with modern instrumentation conduct overall studies and diagnostics of minerals, precious stones and their imitations. Deposits and ore-bearing features of different Far-Eastern regions are selected as geological subjects of research. The best known of them are corund, zircon, spinel, opal, topaz, agate, garnet and nephrite. In recent years field operations are concentrated in Krasnoarmeisk and Pozharski regions and other points of Primorski Krai. The laboratory has four young candidates of science, two postgraduates and students.
The method of thermobarogeochemistry is one of the widespread ways of reconstruction of mineral formation conditions suggested by Nikolai Yermakov, professor of the geological department of Lomonosov Moscow State University. Based on research findings of fluid inclusions in minerals, this method allows to get full information on genesis (origin) and geodynamic conditions for formation of magmatic and metamorphic rocks and also to forecast mineralization of certain semiprecious stones. To carry out fluid inclusion tests the laboratory makes use of the optical polarization microscope NIKON E600 POL (Japan) complete with a computer and software, an optical stereomicroscope for sample preparation, con-
densers, accessories for installation of a digital camera and other components.
The application of the thermobarogeochemical method for handling problems of corund (sapphire) genesis, one of the four most expensive stones in the world, was brilliantly demonstrated by Ella Odarichenko, who defended recently her Ph.D. thesis on this topic. The subject of her research was Nezametninskoye deposit located within Samarkinskaya accretion (from Latin "accretion" as increment or increase) prism of Sikhote Alin ridge (Primorski Krai) and is one of the most promising deposits in Russia in terms of sapphire reserves. They are represented here by rounded crystals of different degree and their fragments up to 20 mm size.
The problem of corund origin always aroused considerable interest among geologists and was a subject of heated discussions. In the available literary sources there is actually no reliable material, characterizing conditions of sapphire origin. This is associated with a number of circumstances. The point is that corund was studied, as a rule, from placers while scarce information on primary deposits did not provide sufficient idea of geology, petrography and other important characteristics of rocks. Besides, the information abounded in uncertainties in diagnostics of minerals and sequence of their formation. Odarichenko's work specified information, which allowed justified judgment on the origin of one of the most beautiful stones, which appeared to be important for making decisions on further exploration and field operations on the Nezametninskoye deposit. The obtained data are also of crucial importance for selection and reliable forecast of sapphire deposits in other regions, in particular, in Thailand and Australia.
Of undoubted interest is a thesis by Vitalia Tishkina devoted to opal, at present one of the most popular semiprecious stones. Noble opals possessing optical effect of opalescence are the most valuable and expensive in world market. This stone is iridescent, it flares up when you turn it, and scintillates displaying unbounded richness of colors. Scientists explain this effect by a diffraction phenomenon: silica globules, which form a mineral structure, are in good order in the noble opal and create a three-dimensional grating. Assessment properties of the gem are determined by coloring, transparency, presence or absence of structural defects, cracks and pores.
Australia is a homeland of opals and is today extracting ~95 percent of the whole mined raw material in the world. The existing concepts of the origin of this baffling mineral are based mainly on research findings of these deposits. But many aspects of this precious stone formation are unexplained.
The Raduzhnoye deposit located within the limits of Western Sikhote Alin volcanic zone is the only "storeroom" of precious opal in Russia. It has become a subject of studies of Tishkina. She conducted a complex analysis of the magmatic system and revealed geological and petrological peculiarities of formation of opal mineralization in volcanites of the Severyanskaya suite and also physicochemical processes of formation of noble opals there. The research findings can be used for development of ennobling methods of off-grade raw material with a view to increase the primary deposit reserves or for search of aggregations of the gem in other geographical points.
The Verkhne-Shibanovskoye deposit located on the slopes of the Siny mountain ridge—the westernmost in the Sikhote Alin mountainous region—has long become a subject of geological studies of our laboratory. Apart from ore mineral resources, including alkaline syenites containing rare earth minerals discovered by Yulia Step-nova, Cand. Sc. (Geol. & Mineral.), there was found a unique cutting and collection material such as crystals and druses of morion, smoke-colored quartz, amethyst, rock crystal, cassiterite and beryl. The laboratory staff determined gemological characteristics of these gems.
Topaz is attributed to the widely spread minerals in the Far East. Its specific prismatic transparent crystals have various coloring in yellow, bluish, pink, greenish and other shades, which can change under action of solar and X-ray beams and also at heating. Crystal sizes reach several kilograms, and some of them are really marvellous. Crystals fit for making jewelry can reach several centimeters.
Topazes of such quality are concentrated in the Zaby-toye deposit in the eastern part of the Primorski Krai. During the geological and petrological studies of the deposit resources the laboratory workers established that this noble stone was closely associated there with ore mineralization. Its prevailing quantity is found in greisens (rock consisting mainly of quartz and light-colored mica). The conducted gemological studies of samples enabled us to attribute them to a cutting raw material of high quality, which can be used in jewelry without ennobling.
It should be noted that by now only the most well-known deposits of semiprecious stones of the Far East are studied. Beyond the scope of studies are left manifestations of chrysolite, beryl, garnet, tourmaline, malachite, agate, chalcedon, cornelian, amethyst, marble onychite and other semiprecious raw material.
Опубликовано на Порталусе 08 ноября 2021 года
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