Learning Semi-Precious Stones, Gems, Minerals
Gemstone raw materials - jewelry, jewelry, ornamental and ornamental stones used for the production of jewelry and artistic products of applied value. Collective decorative materials are sometimes referred to as gemstone raw materials.
Gems (from the Russian. Sam and Tsvetnoy) - precious, semiprecious and ornamental stones (minerals and rocks), which are used as jewelry and ornamental raw materials. Generally transparent or translucent. The term gems is of a historical and everyday nature, it does not belong to scientific terminology and is not strict. At different times in everyday speech and the speech of different specialists, it could refer to translucent or opaque stones, or used to categorize colored-colorless, cut-decorative, precious-ornamental stones. The term has been used in the Urals since the 18th century, it was mentioned by M. I. Pilyaev, but it was widely introduced into practice thanks to the work of A. E. Fersman. According to Fersman’s classification, gems are transparent stones, regardless of their classification as precious or ornamental; opaque minerals and rocks are referred to as “colored stones”.
Gemstones, their physico-chemical properties
- Alexandrite - natural chrysoberyl and synthetic stones
- Diamonds and diamonds are the most publicized jewelry
- Pearls - the lavish gifts of the tropical seas
- Emerald - Thick Green Precious Beryl
- Moonstone: adularia, belomorit - transparent, white and blue stones
- Noble opal , black, fiery, cacholong
- Ruby - red noble corundum
- Sapphire - noble yellow and blue corundum
- Chrysolite, Demantoid - Green Garnet
- Diamond Cutting and Gemstone Cutting Types
Gems and precious stones of Ukraine
- Agate - one of the most attractive gems of Ukraine
- Amazonite - green microcline, green stone of Scythian Amazons
- Beryl - actually Ukrainian beryls, emeralds and aquamarines
- The jet - "black amber" of the ancients or "black ambergris"
- Hematite and Jespilite - Ukrainian Red-Striped Quartzite
- Plaster, alabaster and anhydrite are popular ornamental minerals
- Petrified and fossil wood - the original gem
- Pearls, mother of pearl and other petrified marine animals
- Crystal quartz - rock crystal, amethyst, citrine, morion
- Flint - a patterned and colored ornamental gem with a long history
- Labrador - stone flower of Ukraine, colorful peacock stone
- Opal ungovarovar - green chloropal of the Carpathians and other opals of Ukraine
- Pyrophyllite or agalmatolite - a story from the Neolithic to the present day
- Written granite - ancient letters and hieroglyphics of nature in pegmatite
- Carnelian - a legendary stone, historical legends of carnelian
- Sodalite - a cornflower stone that deserves more attention
- Tiger, cat and falcon eyes from Volyn and Krivoy Rog
- Topaz - the true beauty of Volyn land and the pride of Ukraine
- Tourmaline and its black variety of cherles from the Sea of Azov
- Fluorite - "ore flower", a beautiful and multi-colored stone
- Black Sea trails - the original Crimean green stone the color of the sea
- Amber (burshtin) - a traditional subject of Ukrainian craft
- Jasper rainbow - natural painting and a riot of colors in stone
- Other original stones and minerals found and mined in Ukraine
The articles below and describing the physicochemical properties of stones and minerals are designed for more "advanced" stone lovers, not beginners. The materials below do not contain the magical and healing properties of stones and may present some difficulties for beginners.
Popular gems represented in the CIS (former USSR)
- Diamond is the hardest and one of the most expensive minerals in the world.
- Alexandrite (chrysoberyl) - one of the rarest and original stones
- Beryl (a group of beryls) - heliodors, emeralds, aquamarines, morganites
- Turquoise - a blue and green gem of the East
- Pomegranate (pomegranate group) - popular inexpensive gems
- Jadeite is a popular stone that was used in the Neolithic.
- Pearls - a traditional and favorite decoration of the Slavs
- Quartz (a group of quartz) is an extremely popular mineral in collections
- Corundum (a group of corundums) - colorless corundums, rubies and sapphires
- Lapis lazuli - the blue stone of the high blue mountains of the Pamirs and Afghanistan
- Malachite - Ural malachite is considered the best in the world.
- Jade is the sacred green stone of the Chinese emperors
- Feldspars - Labrador, Moonstone, Sunstone, Amazonite
- Rhodonite (orlets) - a beautiful pink stone of the Urals, a stone of Russia
- Topaz - Blue, Yellow, Wine, and Polychrome Minerals
- Tourmaline - original gems of all colors and shades
- Fluorite is a valuable mineral used in industry.
- Chrysolite - igneous mineral, transparent garnet olivine
- Spinel has recently been separated into an independent class.
- Amber (fossil resin of ancient trees) - frozen time
- Jasper - an unusual mineral with a wide palette of color
Catalog of green stones and minerals
Catalog of red and dark pink stones
|Cinnabar (poison)||Coral||Pyrope (pomegranate)||Ruby (corundum)|
Catalog of blue and dark blue stones
|Turquoise||Saying, kaulit||Dumortierite||Lapis lazuli|
|Sapphire||Sodalite||Topaz||Celestine (poison + radiation)|
Native elements. Very few elements are found in nature in free form as "native". The ease with which metals and non-metals come into contact with other elements, especially with oxygen, determines their presence in the earth's crust almost exclusively in a bound form, in various compounds. Therefore, sometimes it is possible to extract an element using relatively simple operations and then use it in technology; sometimes it requires a complex and expensive process of isolating an element from compounds using a complex of methods. The few elements found in nature in a native form relieve the difficulties associated with separating them from other components (for example, as in the case of noble metals, including platinum), and from the negative environmental impacts that one has to face when working with certain elements, whether metals or non-metals. A completely exceptional case is iron, which enters the earth's crust in a native form in meteorites.
Sulfides include sulfides (metal and sulfur compounds S) and other compounds related to them: selenides, tellurides, arsenides (poisonous compounds with arsenic As), antimonides and bismuthides. This includes oxygen-free compounds formed by the combination of various metals with sulfur, selenium, telurum (having the chemical properties of non-metals) and with semimetals - arsenic, antimony and bismuth. Currently, about 400 mineral species belonging to this class are known. However, they are mainly found in negligible quantities and are of purely scientific interest. But those that are described here are of economic importance. Various sulfides are an important and often the only source of production of elements of extraordinary practical value and necessary for industry. Non-ferrous metals such as copper, lead, zinc, mercury, molybdenum, silver and many rare metals (tellurium, selenium, germanium, iridium, etc.) are obtained mainly from the processing of sulfides.
Halides (or halogens) are chemical compounds formed by the combination of halogens and metals. In nature, the most common halogen is chlorine, followed by fluorine. Bromine and iodine are more rare. Chlorides and fluorides are represented by a number of minerals, while bromides and iodides are scarce in nature. Bromine is only part of one rather rare mineral - bromargirite, and three mineral species are known to iodides. Fluorides are found in hydrothermal veins (fluorite) or, much less often, in pegmatites (cryolite).
Chlorides are more numerous and include a number of fairly common minerals. They were formed as a result of evaporation of the waters of ancient seas or salt lakes (halite - table salt, carnallite) and, unlike fluorite, are absent among vein minerals. Among the products of the activity of some volcanoes, one can also find some chlorides, both relatively common (halite) and rarer species. A significant amount of chloride is formed during the weathering of ore minerals under the influence of atmospheric factors. Among metals, chlorine (kerargyrite), lead, mercury, and copper (atacamite) are most often associated with chlorine.
Oxides and hydroxides. Oxygen is an element very common in the earth's crust. Therefore, it is present as the main component in most minerals. Most often, it is simultaneously associated with two or more elements, one of which is non-metal, such as calcium sulfate (CaSO4, which forms gypsum and anhydrite. From the point of view of chemistry, this substance is considered as a salt of sulfuric acid (H2S0J, and not as an oxide Oxides are those compounds (in our case, minerals) that were formed when oxygen was bound to one of the elements, mainly a metal (such as corundum - Al2O3), as well as to several elements, provided that these compounds cannot be considered typical salts . Many minerals, say, perovskite (CaTiO3) or spinel (MgAl2O4), are considered oxides in some classifications and titanates and aluminates in others, and hydroxides from other minerals of this class differ in the presence, in place of oxygen, of the OH hydroxyl group.
Spinels (oxides). The spinel group includes oxides with the general formula X Y 2 O 4 , where X and Y are metals, respectively, divalent (magnesium, iron, zinc and manganese) and trivalent (aluminum, iron and chromium). A variety of metals can combine in one mineral. In nature, pure compounds are very rare. Spinels crystallize in cubic syngony; twinning is very often observed. Many spinels are the primary crystallization products of magma and are therefore present in many intrusive rocks. They are not uncommon in metamorphic rocks. The most common spinels: spinel itself, magnetite, chromite, franklinite, ganite.
Carbonates. Among the numerous minerals that make up the lithosphere, carbonates play an important role in terms of mineralogy, petrography, and industrial development. They are part of many sedimentary, metamorphic and igneous rocks. Carbonates are the main components, firstly, of limestone, consisting mainly of calcite (calcium carbonate); then dolomites folded by calcium and magnesium carbonate; finally, crystalline marbles, primarily sedimentary, but transformed by metamorphic processes, as a result of which their initial structure changed during the complete recrystallization of calcium carbonate. Carbonates are widely used in industry. They are used as building materials, including finishing; as raw materials for ceramics and as refractories. Carbonates are also ores of many metals, including iron, magnesium, zinc, manganese, lead, barium, etc.
Sulfates are characterized by the presence of SO4 groups in the formula. Tellurides, chromates, molybdates, and tungstates are assigned to the same class (only Te, Cr, Mo, and W are present at site S). As for their origin, it can be noted that some have hydrothermal genesis or were formed during the exhalation (vapor-gas emissions) of volcanoes. Others are of sedimentary origin, mainly marine, still others are secondary formations. Sulphates are extremely widespread in nature. Tellurates and chromates are extremely rare. About fifteen molybdates and tungstates are relatively more common. Minerals of this group are not rock-forming. The exception is gypsum and anhydrite, which compose huge areas of thickness, monomineral in composition.
Phosphates In this category, in addition to phosphates (minerals containing the PO4 group), arsenates and vanadates (minerals containing the AsO4 and VO4 groups are also described. Transitional forms exist between these compounds - from phosphates to arsenates, from arsenates to vanadates and, less commonly, from vanadates In the Earth's crust, primary phosphorus is present mainly in the composition of apatite, which is common in almost all igneous rocks, in pegmatite veins and in some ore deposits. Weathering, dissolution and transfer processes ensure the accumulation of phosphates Atoms in soils and sea water. Living organisms extract phosphorus from them, which is necessary for their existence. The accumulations of the remains of organisms and their excrement are deposits of great industrial importance. Arsenates and vanadates are mainly secondary minerals formed in deposits of a complex composition enriched with sulfides , mainly arsenic and cobalt.
Silicates . Most of the lithosphere consists of silicates, a very common mineral among both igneous and metamorphic and sedimentary rocks. Their significance is great not only from the mineralogical (including ornamental, decorative and jewelry stones) and petrographic point of view, but also from the point of view of raw materials for various industries. The composition of silicates always includes silicon, which is combined with other elements, such as oxygen, aluminum, iron, manganese, magnesium, calcium and many others. They give rise to many minerals, often very complex in composition, which can often be easily determined without even using modern, very advanced research methods. It has already been noted above that silicon is part of several different modifications of silica represented by quartz, tridymite and cristobalite. They are considered as oxides in this book, but a number of authors classify them as silicates because of the great similarity of their structures with the structures of tectosilicates.
Structurally, in the crystal lattice of silicates, each Si silica ion is located in the center of the tetrahedron, on each of the four vertices of which there is an oxygen ion O2. Together, the silica ion and the four oxygen ions surrounding it represent a radical, or a complex anion, the tetrahedral group SiO4 +. It is the main structural element of all silicates. Tetrahedra in the structure can be isolated - as in the case of non-silicates; but they can also unite in various ways, creating other complex radicals. The combination of tetrahedra serves as the basis for the classification below. The tetrahedra are joined using an oxygen ion common to two neighboring tetrahedra. In a situation where all four oxygen ions in a tetrahedron are common to him and neighboring tetrahedra, free valencies no longer remain. Then no cation is able to adhere to the complex radical unless one or more trivalent aluminum ions replace one or more tetravalent silicon ions, thus freeing up an additional negative valence. Aluminum in silicates can play a double role. If it is part of the tetrahedra, i.e., is part of the anion radical, we are dealing with aluminosilicate. If it acts as an extra-tetrahedral cation, then we are talking about aluminum silicate. If aluminum plays both of these roles at the same time, then we are talking about aluminum aluminosilicate. The complex crystal lattice of silicates often contains additional anions that are unusual for it and perform the task of compensating for free valencies. Often there is water, both in the form of hydroxyl and in molecular form. In the latter case, it fills the channels of the crystal lattice, but its bonds with the lattice are very weak.
According to the latest scientific ideas about the structure of silicates, they, in accordance with the method of grouping SiO4 tetrahedra, are divided into the following subclasses:
Non-silicates (orthosilicates) - silicates with isolated or independent tetrahedra.
Sorosilicates (diorthosilicates) are silicates with isolated Si2O7 groups.
Cyclosilicates (ring silicates) - silicates with tetrahedra, combined into rings of triangular, quadrangular or hexagonal shape.
Inosilicates (chain silicates) are silicates with tetrahedra connected in single or double chains.
Phyllosilicates (layered silicates) - silicates with tetrahedra, combined in layers.
Tectosilicates (framework silicates) are silicates with tetrahedra connected in the form of three-dimensional structures.
Grenades (silicates) . A group of fairly common minerals in nature, often difficult to distinguish from each other. Their generalized formula can be written as follows: X3Y2 (Si04) 3, where X is calcium, magnesium, ferrous iron and manganese; Y - aluminum, ferric iron, chromium, titanium, zirconium and vanadium. Garnets crystallize in cubic syngony, very often in the form of well-formed crystals without cleavage. Based on the presence of trivalent elements in the chemical composition, they can be divided into the following series: aluminum-containing garnets (pyrope, almandine, spessartine, grossular); iron garnets (Fe3 +) - calderite, andradite; chromium-containing garnets (uvarovit), garnets containing titanium, zirconium and vanadium (kimceite, goldmanite).
Epidotes (silicates) . Epidotes are very important minerals from the point of view of petrography: being common elements of igneous and metamorphic rocks, they form isomorphic series of mineral species, each of which indicates the genesis of the rock in which it is found. The two main epidotes are clinocytosis and epidote proper. The first combines calcium and aluminum; in the second, aluminum is partially replaced by iron. The group also includes piedmontite and allanite, which are respectively manganese and cerium-containing epidotes. In addition, zoisite, which is a heteromorphic analogue of clino-zoisite (it crystallizes in another syngony - rhombic instead of monoclinic), is also referred to as epidote. Here it is described as an addition to this group.
Pyroxenes (silicates) . The pyroxene group includes a large number of minerals, between which isomorphic series exist. In terms of crystal structure, they are all monoclinic. The exception is a number of enstatitis - hypersthenes, representatives of which belong to rhombic syngony; adjacent to this series is another, with identical chemical composition, but with monoclinic syngony (a series of clinoenstatitis - clinohypersthene). The remaining ranks: diopside - hedenbergite; spodumene - jadeite - aegirine; Dialag - Augite - Farsaite. Isomorphic substitutions in pyroxenes are carried out in different structural positions, moreover, different elements can enter the same position, and the same can be entered into different positions.
Amphiboles (silicates) . Amphiboles, like pyroxenes (with which amphiboles have many common morphological and chemical features), belong to the subclass of inosilicates, but differ in the presence of SiO4 tetrahedra in the crystal lattice. The optical properties are diverse, and the chemical composition is rather complex. In addition, they are wider and more common than pyroxenes. Amphiboles are characterized by elongated prismatic habit; cleavage, manifested along the directions of the prism, perfect. Like pyroxenes, amphiboles have monoclinic (a number of cummingtonite, actinolite, hornblende and glaucophane) and rhombic (a number of anthophyllite) representatives.
Mica (silicates) . This group of philosilicates includes numerous and important minerals, which in terms of chemical composition can be defined as silicates of aluminum and alkali metals, which also contain magnesium, iron, hydroxyl group and fluorine. If the number of aluminum, magnesium and iron ions is 2, these mica belong to the muscovite series (paragonite, muscovite, glauconite, celadonite, and roskoelite). If this number is 3, such micas belong to the biotite series (phlogopite, biotite, annite, lepidolite, cynivaldite). Mica crystallizes in monoclinic syngony, usually in the form of elastic plates, of low specific gravity, with pseudo-hexagonal or irregular outlines; they are characterized by perfect cleavage, which is very easy to separate, low hardness and varied color. In nature, micas are very common and abundant: they can be found as essential components in a wide variety of igneous and metamorphic, as well as sedimentary rocks.
Chlorites (silicates) . These numerous minerals belong to the group of philosilicates. They have direct analogies with mica, but differ in their chemical composition. Chlorites are characterized by a high water content and a complete or almost complete absence of alkali. From a chemical point of view, they can be considered as silicates of aluminum, magnesium and iron, as a rule, without an admixture of alkali metals. They crystallize in monoclinic syngony in the form of small irregular scales of pseudo-hexagonal outlines, with perfect cleavage resembling cleavage of mica. Chlorite plates, unlike mica, are flexible, but not elastic. Chlorites are often observed in the form of rather dense scaly aggregates, massive powdery clusters, fine-grained grains and worm-like clusters of plates. For chlorites, widespread and abundant in nature, the green color of various shades is characteristic. Of chlorites, pennin, clinochlorine, and kemmererit are considered.
Feldspars (silicates) . Feldspars are the largest and most well-known group of minerals, which are the most important rock-forming components of rocks. They take part in the formation of a wide variety of rocks - both igneous, including intrusive, and effusive, as well as crystalline schists and sedimentary rocks. From the point of view of chemical composition, they are considered as aluminosilicates of potassium, sodium, calcium and, less commonly, barium, containing also impurities of other elements, such as lithium, cesium, rubidium, magnesium, iron, titanium, etc. The most significant members of this family are the result of a combination three main components: potassium aluminosilicate, sodium aluminosilicate and calcium aluminosilicate. A rare barium aluminosilicate adjoins them, Celtic Albit and anorthite are two extreme members of the isomorphic series of plagioclases, which also includes oligoclase, andesine, labrador and bitovnite. Plagioclases crystallize in two versions, high temperature and stable at low temperatures.
Feldspathoids (silicates) . Under this name a group of minerals is combined that are very similar in chemical composition to feldspars. It includes aluminosilicates of potassium, sodium, lithium and calcium. The composition of their crystal lattice may include extraneous anions, such as SO4, C03, and OH, water molecules, and elements such as fluorine and chlorine. Some researchers do not recognize the existence of this group, which nonetheless includes about twenty minerals, from petalite to lapis lazuli.
Zeolites (silicates) . Zeolites are mineral species that can be defined as aqueous aluminosilicates of several alkali metals (such as sodium and potassium) and several alkaline earth metals, such as calcium and barium, less commonly strontium and magnesium. From other silicates, they are distinguished by the ability to increase in volume and boil when heated. This property was reflected in the name of zeolites (in Greek - "stone that boils"). It is associated with the behavior when heating water entering the crystal lattice, but weakly associated with the crystal structure. Zeolites are minerals of secondary origin. They fill the cracks in the rocks and voids in the main igneous rocks of the basalt type. Zeolites are also found in geodes of granite rocks, in the form of mineral-filled cracks in gneiss rocks and sometimes in some ore-bearing veins of hydrothermal origin.
Usually zeolites are not used in the jewelry industry, but the ever-increasing role of these formations in technology and medicine makes them truly precious. It is no accident that the zeolites received the figurative name of the "philosophical stone of the 21st century." Zeolites are a whole family of minerals (water-containing aluminosilicates), including cations of potassium, sodium, calcium and magnesium. Their world production and consumption in 2000 alone exceeded 20 million tons. The term "zeolite" is translated from Greek as "boiling stone" and indicates the low melting point of this mineral. Since zeolites are a kind of "porous crystals", they are able to exchange ions with the environment. Their unique sorption properties are based on this effect. In medicine and the food industry, zeolites are used as food additives that can remove harmful metabolites from the body without affecting proteins and other macromolecules. Some zeolites bind and remove harmful substances from the body from the body and supply it with trace elements necessary for normal physiological activity.
Organic matter This group is represented by substances formed due to organisms that lived in past geological eras. They petrified over time (like amber) or were replaced by different minerals (like silicified wood). In this understanding, a wide variety of materials (including fossil coals) should be included here. In mineralogical systematization, however, only those attributed to precious or ornamental stones are considered.
Via jewelery.org.ua, geokniga.org, mmus.geology.pu.ru, mirkamney.moy.su, kristallov.net, webmineral.ru, geo.web.ru, catalogmineralov.ru, mindraw.web.ru, mining -enc.ru, wiki