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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

CALCITE, GROUP: CALCITE, ARAGONITE, BARYTOCALCITE, GAYLUSSITE, IKAITE


CALCITE group (Calcit—Calcite—Кальцит) (Pliny the Elder, 77 in Freiesleben, J.K. 1836), from Lat. “calx” – lime. Here is also rocks formed with calcite and polymorph modification of calcite – aragonite is described, as well as some other carbonates, which have constant miscibility with calcite: barytocalcite, gaylussite, ikaite.

Composition & Properties. Carbonate – Ca[CO3], trigonal system. Hardness 3. Density 2.6-2.9. Glass luster to pearl one. Cleavage in three directions. Fragile. The shape of calcite crystals depends on the conditions of their forming. Transparent to non-transparent. The biggest crystals are found at deposits of Icelandic spar, where their size reached 7 m. long with the weight up to 25 tons. Aggregates of calcite are rather different in character. Fine-fibrous aggregates resembling gypsum are called fibrous calcite, satin spar or silk spar; also lamellar calcite. In karst cavities among limestone, calcite onyx forms stalactites, stalagmites and helictites. They also find cave pearls. In sedimentary rocks, they find chalcedony-like calcite – prunnerite and concretions of black calcite – bruyerite. As calcite, pseudomorphs replaced many minerals: anhydrite, apophyllite, baryte, gypsum, quartz, fluorite, chalcedony, celestine, cerussite and others. In their turn, opal, chalcedony and other minerals replace calcite. It exists in the content of pearls, nacre, modern and fossilized shells and corals, as well as belemnites and ammonites. Calcite skeletons of the extinct mollusks Belemnites, or devil fingers received their name because of their oblong shape. Beside calcite, they are replaced also with aragonite and pyrite. They are often used as amulets and adornments. In the U.S.A. a pseudomorph of calcite on fossil coral is popular – Petoskey stone. Because of their low hardness, calcite and minerals of its group are valued as cheap gemstones.

Color. Calcite as crystals of Icelandic spar is transparent, but more often its non-transparent crystals and aggregates of different shapes and tones are found. Color: colorless, white, gray, yellow, rose, green, blue, red. In large crystals color can be zonal. They classify varieties of calcite with different colors, which depend on admixtures. Ferrocalcite is yellowish or brownish because of the admixture of iron. Manganocalcite is dark rose, rose or yellow because of the admixture of manganese. Cobalt calcite is pink or lilac-red because of the admixture of cobalt, and a prunnerite is violet. The admixture of nickel gives light apple-green color to calcite. In crenite inclusions of fine-dispersed hard bitumen produce yellow to brown color. Anthraconite is gray to black because of the admixture of coaly small parts; and hematokonite is blood-red because of the admixture of hematite. Calcite can be red because of cinnabar inclusions and of cuprite inclusions – cuprocalcite; green – because of chlorite and celadonite; bluish and greenish – because of pyrite. Malachite calcite is green because of malachite; and its blue variety cerulén – because of azurite. Sometimes, ornamental mineral inclusions in calcite make it especially valuable from the decorative point of view. Those are transparent crystals of calcite with inclusions of native copper and pyrite. Among optical effects of calcite, we should mention, first of all, its high double refraction, which produces bifurcation of an image when looking through a transparent crystal of it. Fibrous variety of calcite – satin spar and half-transparent orange-colored calorango in cabochon displays the effect of cat’s-eye. Fine-leafy argentine is characterized with nacre luster and inner light reflex resembling the iridescence.

Ornamental rocks. Among ornamental stones with calcite in their content, we should mention limestone, calciphyre, marble, ophicalcite and travertine.

Limestone is a sedimentary rock mainly of marine origin, composed with calcite, more rarely – with aragonite. According the specifics of their content and structure, there are classified in the following ornamental varieties. Agate-like limestone with fine rhythmic-stripped texture, which depends on the alternation of red, orange-red and white layers. Marl limestone is an even-colored rock of the tone of ivory, as well as gray, light blue, green ones, decorated with manganese-dendrite patterns. Bioorganic limestone enriched with skeleton remains of sea and vegetative organisms, including coral limestone, or Petoskey stone, shelly limestone – lumachelle, stromatolitic limestone, or algal limestone.

Calciphyre is an uneven-grained metamorphic rock, which is formed under the recrystallization of limestone. This rock looks like marble, and because of the content of silicate minerals can be of interest as an ornamental stone.

Marble is a general name for metamorphosed limestone and dolomites, which are available for polishing. It is a non-transparent, sometimes, translucent rock, composed mainly with grains of calcite or dolomite. Its structure is from fine- to coarse-grained, texture is massive, and according the dispersion of color it can be stripped, spotty or other one. Ornamental figured marble and color marble are popular for stone-carving and coating; there are numerous varieties of these stones (See syn.). Pure from admixtures marble is white. Their differentiation in color depends on mineral admixtures. Among them we should mention: hard bitumen – in Egyptian marble, hematite –in red marblegriotte, graphite – in black marble, brucite – in light green brucite marble, serpentine – in green antique marble and Levant marble, chlorite – in Kibic-Kordon marble, fuchsite – in chipollino marble. Among ornamental varieties are also marble conglomerate – pudding stone and marble breccia.

Ophicalcite is a rock composed mainly with calcite and serpentine. This ornamental and carving stone is easy for processing and well-polished. For coating it was used even in Ancient Rome and Byzantium. According the content, it is marmorize limestone with veins and spots of serpentine. After its ornamental properties they classify such varieties: straight-stripped – light green of various tones; broad-stripped. – yellowish-green; bandy and veined-spotty – variegated in color limestone.

Travertine is a rock, which is solid – opposite to tufa. It is formed as a result of precipitation of calcite from calcareous waters. Usually, travertine is light colored or light brownish because of Iron oxides, non-transparent, stripped in texture. Its ornamental varieties are used in stone-carving.

Deposits. Calcite in large quantities is precipitated through bioorganic and chemical genesis ways; it is a rock-forming mineral for limestone and other rocks. From rich with calc hot and cold springs it is deposited as calcareous tuff – travertine onyx and marble onyx (See aragonite). In hydrothermal veins calcite is rather often the main cementing material. In the process of metamorphism carbonate rocks are easily recrystallized into marbles, calciphyres and ophicalcites. In metasomatic rocks, such as skarn, calcite exists often, but in magmatic rocks and in granite pegmatites it doesn’t form significant accumulations as an ornamental stone. In Russia, the best transparent crystals of calcite are found at deposits of Icelandic spar in Evenkia, in the basin of the Lower Tunguska River, Krasnoyarsk Region, and in Yakutia, in the basin of the Vilyui River – Dzhekinda and others deposits. In the end of 1980-s, in Evenkia, at the Stolbovoye deposit they extracted crystals of Icelandic spar 80 cm. and 93x53 cm. in size, 302 and 310 kg,. At the Razlom deposit, they found a crystal 2 m. long. An example of colored jewelry-ornamental varieties of calcite in Russia, in the Subpolar Urals Mts., are findings of rose calcite with the manganese admixture at the Dodo deposit; and in East Transbaikalia – at the Klichka deposit. Among the other varieties in Pribaikalia, such ones are special interest: light blue-green calciphyre with the nickel admixture from the fold Ulungui in the region of Slyudyanka. In the Primorskiy Region, fine crystals of the various form up to 40 cm. in length found on the Dal’negorskoye deposit. In Tadzhikistan, at the Dzhizhikrut deposit, in the Hissar Mts. they find red calcite with the admixture of cinnabar.

In Norway, in calcite crystals from the Kongsberg deposit, there are decorative inclusions of native silver. In Iceland, large deposits of Icelandic spar are almost completely worked out. There, at the Helgustadir deposit, Eskifjord, they extracted the biggest crystal of Icelandic spar, 6x6x3 m. and 280 tons. In the south-east of Germany light yellow massive calcite with bright-red and white stripes was extracted at the Bottlingen deposit, Baden-Württemberg. Rose manganocalcite was extracted in Slovakia, in the region of Banská Štiavnica; also in Bulgaria – at the Madan deposit and in Sweden – at the Långban mine. In Hungary, at the Parádsasvár deposit, they extracted collection samples of transparent columnar crystals of calcite up to 30 cm. long – kanonenspath, and in the Romania at the Hârja deposit – snow-white sphaerolites of calcite up to 15 cm. in diameter, sometimes they were half-black. In Spain, in the Peramera locality, Catalonia, most interesting is purple-red cobalt-calcite. From deposits of Madagascar and Namibia blue calcite is coming. In Namibia, at the Tsumeb deposit, they find rose calcite, the similar one is in Congo (Kinshasa), at the Mashamba mine, West Sheba Prov. In South Africa, in Northern Cape Prov. there are small deposits of Icelandic spar, and at the Kuruman deposit – rose manganocalcite. In Australia, in New South Wales, at the Huskisson deposit, they find pseudomorhs of calcite on glauberite. In the U.S.A., in Minnesota at the Joplin deposit, Jasper Co., they found a crystal of calcite 1 m long. In New Jersey, at the deposits Franklin and Sterling Hill they extracted manganocalcite. In New Mexico, at the deposits Harding and Iceberg Claim, Taos Co., they found calcite crystals more than 3 m. In the New York State, at the Balmat area from a calcite crystal they received a faceted stone 492 ct. In Mexico, in the Chihuahua State, they extracted Icelandic spar in crystals up to 70 cm. long. In the Baja California State, orange and brown-orange calcite at the Rosarita Beach deposit is known. From a transparent part of such crystal they received a faceted stone 170 ct. In Chihuahua State, pale green calcite is mined in Madera; also blue-green aurichalcite-filling crystals calcite at the Ojuela mine, Durango. In the Zacatecas State, apple-green calcite in druses aggregates comes to the market from the region of Conception del Oro.

Limestone of ornamental quality are various and widespread. In Yakutia, as an ornamental they use silification bioorganic limestone of vinous-brown color with inclusions of shells under the trade name biolite. In the Ukraine, in Crimea, bioorganic limestone is extracted near the Ai-Petri Mt. In Italy, in Florence, they have extracted marl limestone under the trade name landscape stone since the Middle Ages. In Austria, there is the most beautiful ornamental shelly limestone – dark brownish fiery marble, or lumachella from the Bleiberg deposit, Carinthia. It is characterized with bright iridescence because of containing in it nacre shells. In Belgium, a deposit of black limestone with white calcite veins – Belgian black marble was exploited. A similar deposit of French black marble is known in the region of Calais in the north of France. In Great Britain, black bituminous limestone – Ashford black marble has been used for Florentine mosaic since the 16th cent. There also swamp limestone of light bluish-gray or reddish-brown tone is popular; it contains shells of fossilized freshwater snails. It is extracted in the Dorset Co. under the trade name Purbek marble. Limestone is used often for tables, souvenirs and big, not very expensive adornments.

Marbles in Russia are represented with numerous varieties at many deposits. Some of them are especially interesting from the decorative point of view; they possess unique, individual types of coloring. In Karelia, Belogorskiy marble has been known since the 18th cent.. It was widely used in the decoration of palace interiors in St Petersburg ensembles. Its Belaya Mt. deposit is situated to the northwest from Kondopoga, on the bank of Khizhozero Lake. The color of this marble is variegated in brownish-rose tones. The most ornamental varieties are tender rose and cherry-red in color. In the Urals, the following kinds of marbles are extracted: light rose Polevskoy marble – Polevskoye deposit; dark gray to black with white veins Karkodinskiy marble – Karcodinskoye deposit; grayish-yellow Phominskiy marble with a tree-like pattern – Phominskoye deposit; variegated, breccia red and lilac Nijni Tagil marble – Nizhnetagil’skoye deposit. Fine-grained translucent marble of the Koelginskoye deposit is close to sculpture kinds of Parian marble from Páros Is., Greece, and Carrara marble from Carrara deposit, Italy. In the Altai Mts., they extract green, red and white breccia, patterned marble at the Pushtulimskoye deposit. At the Oroktoiskoye deposit marble, is from golden-yellow and rose-lilac to variegated pale color with hematite veins. In the Krasnoyarsk Region, at the Kibik-Kordonskoye deposit near Sayanogorsk, pale rose marble is not worse than the best Italian marbles. There also marble with dark green stripes on rose back-ground is found. In the Irkutsk Region, they extract light blue translucent marble at the Sliudyanskoye deposit. In the Khabarovsk Region and Magadan Region, there is the Kul’durskoye deposit of green figured marble; and Birakanskoye deposit of rose-lilac marble with net pattern. In the Primorskiy Region, near Dmitrievka, they exploit the Knorringskoye deposit of marble conglomerates and conglomerate-breccia. These are variegated in color, massive rocks with egg-shaped fragments from 0.5 to 20 cm. They are white, rose, red, green and black.

Among the other countries, we should mention Italy first of all: in the Apuan Alps Mts. – Carrara with white Carrara marble; near Verona and in Venice – rose marble; near Sienna – greenish one; on the coast of Golfo di La Spezia– black, spotty one; in Colle di Val d’Elsa, in Tuscany – yellow one; in Bagno a Ripoli – ruini marble. In Greece, on the Euboea Is. marble with white and green layers is very popular; it is called chipollino marble. In Australia, they extract stripped zebra marble as an ornamental stone.

Ophicalcite. In Russia, the most part of exploited deposits of ophicalcite is situated in the South Urals: Medvedevskoye – in the Region of Zlatoust and Chereshkovskoye – not far from Satka, in the Chelyabinsk Region and others. In the Irkutsk Region, the Alchazaiskoye deposit is known near Cheremkhovo with calculated resources of ornamental stones. In Georgia, they have explored the Sadakhlinskoye deposit. In Kazakhstan, ophicalcite is represented with the Maikul’skoye demonstration in the Jambul Region. In Uzbekistan, there is the Kurgashinkan deposit of ophicalcite near Olmaliq (Almalyk); in Kyrgyzstan – Gavansay; in Tadzhikistan – Kansay. In Mongolia, they have explored the Dzalungozin deposit of ophicalcite. In China, translucent ophicalcite is used in stone-carving as imitation of nephrite. Its large deposit is exploited on the Liaodong Penin., Liaoning Prov.

Travertines. This ornamental variety of calcite rocks is widespread in Russia, in the Northern Caucasus and in Transbaikalia. In the Ukraine, large territories with travertine are known in the Rivnens’ka Region. In the other countries, we should mention the best ornamental travertines of the Tivoli deposit near Rome, Italy.

Synonyms. Calcite – Andradamas, antique name | Atlasspath, Germ. | Atlasstein, Germ. | Bruyerite, after the discovery location near Bruyéres, in the north-east of France | Silvery chalk | Icelandic crystal | Kanonenspath, Germ. | Papierspath, from Germ. “Papier” – paper, because of its fine-plate aggregates | Prunnerite, after the Ital. scientist Prunner | Sericolite, from Gk. “serikos” – silky and “litos” – a stone, in fine-fibrous aggregates, after its luster, obs. | ~ spar: aspidian ~, calcareous ~, dog’s teeth ~, double ~, double refraction ~, doubling ~, feather ~, gun ~, in the shape of prismatic crystals; Greenland ~, after the discovery location; layered ~, nailhead ~, Niagara ~, after the discovery location near Niagara, Lockport deposit N.Y. the U.S.A.; paper ~, scheelite ~, shiver ~, slate ~, table-like ~, after the shape of crystals | Duplicate stone | White silk stone, in fine-fibrous aggregates, after its silk luster.

Ornamental stone – Calcaire alabaster | Brecciated limestone | Reef limestone | Shelly limestone | Lumashel (lumachelle) from Ital. “lumacella” – a shell | Ashford black marble, bituminous limestone, after the discovery location near the village of Ashford, Derbyshire, England | Fiery marble | Lumachella marble | Bone stone | Petoskey stone, after the discovery location near Petoskey, Michigan, the U.S.A. | Travertine, from perverted Lat. “lapis Tiburtinus” – a stone from Tiber, Italy.

Marble, from Gk. “marmareous” – sparkling – Bardiglio, Ital. | African breccia | Brocatello, Ital., marble breccia with fragments variegated in color | ~ marble: African ~, alabaster ~, bamboo ~, after its texture; bioorganic ~; Carrara ~, after the discovery location in Carrara, Italy; Egyptian ~, from the Prov. Specia and Liguria, Italy; eye ~, figured ~, Florentina ~, Irish green ~; griotte ~, after its color, from Fr., a name of a cherry specie, from a deposit near Narbonne, Langedoc-Roussillon, France; landscape ~, Levant ~, after the discovery location near Levanto, Italy; Mexican ~, Parian ~, after the Paros Is. in the Aegean Sea, Greece; Picasso ~; Purbek ~, after the discovery location at a deposit in Dorset, Great Britain; ruini ~, after its pattern; serpentine ~, shelly ~, Sienna ~, after the discovery location near Sienna, Italy; spotty ~, with petrified remains of sea-lillies; statuary ~, Veronese ~, after the discovery location in Verona, Italy; zebra ~, after its texture, from Australia; zipollin (cipollin) ~, Ital., after the similarity of its pattern with onion. | Yaqui onyx.

Ophicalcite, from Gk “ophis” – a snake and “calcite” – after its content and color – Alpine stone, after the discovery location at the Alps.

Quality improvement. Transparent crystals of calcite are irradiated to strengthen its color. Grained aggregates are colored green – Mexican imperial jade, Mexican jade. Porous carbonate rocks – calcareous tuff, shell rock and travertine are improved with the method of their impregnation with resin.

Treatment. Transparent calcite is faceted only in collection purposes. In Russia, from Icelandic spar of Evenkia they have faceted a stone 474 ct. In the U.S.A., in the Harvard University, a similar faceted stone is kept, 1,260 ct., and in the New York State from a calcite crystal from the Balmat area, St Lawrence Co., they have faceted a stone 4,620 ct. In the Smiths. Inst., Wash. There are two golden-yellow faceted Icelandic spar from Brazil, Bahia – 75.8 and 45.8 ct. In the Museum of Algeria, they expose a model of sarcophagus, 25x30 cm., made from a crystal of golden-yellow calcite. Ornamental varieties of carbonate rocks, including ornamental marbles, are wonderful material for stone-carving; they are well-polished. They are used also in stone mosaics. In museums of different countries, many works of art from marble are exhibited: sculptures and vases by Ital. masters, mosaic tables, incrustations and so on. In the architecture they use such decoration material as stuck, which imitates marble.

Even in 1830-s ophicalcite in Russia was used for halts of Damask-steel blades made in the Urals. In the lab of stone of the Academy of Architecture of the USSR, they have made a vase from Ural ophicalcite.

In the U.S.A., Petoskey stone has been serving as an official symbol of Michigan since 1965.

Similarity. Calcite looks like aragonite and other carbonates.

Aragonite (Aragonit—Aragonite—Арагонит) (Davila, 1767 in Werner, 1796), after the Aragon Region, Spain, where pseudohexagonal twin crystal were first discovered. Carbonate – Ca[CO3], orthorhombic system. Hardness 3.5-4. Density 2.9. Glass luster, silk one. Cleavage in one direction, Fragile. Aragonite is less spread than calcite, and it has subordinate significance as rock-forming mineral. It is typical for it to possess columnar to needle crystals and fin-fibrous aggregates with silk luster. Transparent to non-transparent. Color: colorless, white, reddish, greenish, light bluish to dark violet and brownish. Blue-green variety of aragonite is called iglite; and blue aragonite, which color depends on inclusions of aurichalcite, has its own trade name zeiringit. Aragonite is in the composition of nacreconchite, pearls and corals, fossil nacre – ammolite.It forms pseudomorphs on gypsumaphrite or foamy spar. In sedimentary rocks aragonite is often exists as pseudomorphs on bioorganic materials. The widespread ornamental rock composed mainly with aragonite is marble onyx. It is formed in hot mineral springs in volcano zones as coats, veins and wandering forms. In caves they often find its stalactites and stalagmites, wandering forms of cave onyx, and also coral-like aggregates – gelictites. There, also cave pearls can be found, which are formed from cold calcareous solutions in the shape of concentric-foliated concretions. Usually, they display surface roughness, but polished in water flows they can display pearls luster. Such concretions, or oolites are composed with crypto-fibrous aragonite – ctipeite (ctypéite). Their color is mainly white, yellowish-white, light green, violet, light blue because of the admixture of copper. They are non-transparent and reach 2.5 cm. in diameter. Sometimes, they are used in adornments for imitation of pearls. In latter hydrothermal processes, in serpentinization of basic rocks, aragonite forms veins, fills cavities in basalt lavas, deposits from hot springs as travertine. Mixture of aragonite with calcite in mineral springs of the Erzberg deposit in Austria has been called erzbergit.

Marble onyx. Unlike travertine, it is translucent to half-transparent. It is composed with aggregates of aragonite or calcite, which have band-concentric pattern. Beside traditional stripped varieties, there are spotty, veined and breccia ones – organite. Their color varies broadly from honey-yellow and rose to dark brown and green.

Deposits. In Russia, in sedimentary layers of the Volga Region, near Ul’yanovsk, they find fossil ammonites up to 30 cm. in diameter, replaced with calcite and aragonite with admixture of pyrite, which received the trade name simbirzits. They are popular as collection material, and their ornamental parts are used in jewelry. In the South Urals, at the Bakal’skoye deposit, aragonite is developing in weathering crust on siderite. In South Kyrgyzstan, near Khaydarken, at the Khaydarken deposit, aragonite is represented with stalactites and resembling corals gelictites white, dark blue and salad-green color, and blue aragonite at the Aksur deposit, near Khaydarken, was found. In Kazakhstan, aragonite in significant accumulations exists at the Abail deposit 70 km. NEE of Chimkent (now Shymkent), and at the Belinskoye deposit, in Turgai. In Mongolia, at agate deposits of the Arts Bogdo Range, they find chalcedony pseudomorphs on aragonite.

In Romania, at the Baita deposit, they find radial-rayed aggregates of blue aragonite. There, at the Ζeleznik deposit, near Sirk, in iron ores they find isolations of snow-white aggregates of aragonite, so called “iron flowers”. In Czech Rep., transparent, gem-quality aragonite at Všechlapy, Jihoçeský Kraj, was extracted, where it was represented with colorless, light bluish, rarely greenish and polychromatic transparent varieties. Faceted stones up to 100 ct. were made from them. In thermal springs of Karlovy Vary, deposits of sprudelstein are represented with foliated crusts and stalactites of aragonite, or Karlovy Vary spring stone. Crystallization of aragonite in these springs is going on the surface of any objects, for instance, on grains of sand – small spherical oolites are formed on them, which are forming oolitic aragonite, or pisolitic aragonite stone, or roe stone. In this way aragonite deposits on petals of living flowers, these formations become nice souvenirs for tourists. In Slovakia, at the Podrechany deposit, crystals of aragonite reach 30 cm.. In Czech Rep., yellow transparent aragonite crystals to 20 cm. occur at Horenec, and lavender crystals at Všechlapy, near Teplice, both Severoçeský kraj. In Austria, at the Erzberg deposit, Carinthia, coral-like aragonite is represented with iron flowers. In Italy, on the Sicily Is, at deposits of sulfur they find crystals of aragonite up to 15 cm. long. There, also ornamental aragonite is known, which is sky-blue or greenish because of the admixture of copper. In Greece, to the south from Athen, near Lavrion, they extracted large crystals of light blue aragonite. In Spain, at the Minglanilia deposit, near Quanc, La Mancha Prov., they find triple crystals of aragonite up to 25 cm.; and in the Aragon Prov., at the Molina deposit – colorless crystals of aragonite. In Great Britain, in Cumbria, they found radial-rayed greenish-blue spherical aggregates of aragonite and transparent crystals of significant size. In Namibia, at the Tsumeb deposit, crystals of aragonite to 20 cm., containing numerous inclusions of cerussite, are known under the name tarnowskite, or lead aragonite. They find also beautiful crystals nicholsonite – zinc aragonite there. In Japan, at the Matsushiro deposit, Shimane Pref., aragonite forms radial-rayed and spherical aggregates up to 40 cm. in diameter. In Canada, they find non-transparent aragonite – calcentine of variegated color with spots and stripes of red, blue and yellow tones. In Bolivia, at the Corocoro deposit, near La Paz, there are native copper pseudomorphs on aragonite, and in the Argentina, at the Paso de Indios deposit, Chubut Prov., there are chalcedony pseudomorphs on aragonite. In Peru and Chile, they extract light blue gem-quality aragonite.

Marble onyx. In Russia, its deposits of significant thickness are situated in the Saratov Region, at the Berëzovoye deposit. In the Altai-Sayan Mts., it fills karst caves. In the Krasnoyarsk Region deposits of marble onyx are known in Evenkia and near Krasnoyarsk – Torgashinskoye, in Khakasia – the Syiskaya cave, and in Yakutia – the Tamuldurskoye deposit. In Turkmenistan, there are numerous deposits of marble onyx: in Ganja cave, Karla cave and Kip Kurten cave system on the western slope of the Kugitantau Ridge and Krasnovodskoye deposit. The size of stalactites of marble onyx in these caves reaches 1x0.5 m. and more. In Kyrgyzstan, in the Ysyk-Köl Lake Region, there is its Dyuresu deposit. In Uzbekistan, marble onyx was extracted at the Kumushkan deposit, in the spurs of the Chatkalskiy Ridge, Toshkent (Tashkent) Region; as well as at the Gunjak deposit in the Samarqand Region. In the southern part of the country there are deposits Kugitan-Tau and Tashkurgan, Qashqardaryo Region. In Tadzhikistan, marble onyx is discovered at the Takob group of deposits, at the southern slope of the Hissar Mts.. In South Kazakhstan, in the Kara-Tau Mts., they discovered a deposit of honey marble onyx. In the Caucasus, they extracted several deposits of marble onyx: in Armenia – Agamzalinskoye, 12 km. of Erevan near Verin, Artashat, Anakavan in the Gegashen (Razdan) and Vedinskoye; in Azerbaijan – the Sirabskoye deposit near Nakhichevan and Tutkhunskoye in the Kelbajar Dist.; in Georgia – the Marmalo Mt. deposit in the Akhalts’ikhe Dist. and Jarji near Tbilisi.

In Algeria, there is the largest deposit of marble onyx – near Mouaskar, Oran Prov.; and in the Atlas Mts., in the Constantine Prov. There are deposits of bright red, rose, light blue and green marble onyx. In Egypt, along the Nile Valley, there is a deposit of translucent amber-yellow marble onyx near Assiut (Asyüt), and white Egyptian alabaster in Bani Suwayf Dist., also near Lucsor. In the southern part of Afghanistan, there is the similar Malik Dukhan deposit in the desert of Registan, Gilmend Prov. In Iran, in the north-west of East Azerbaijan, marble onyx is known as Tabriz marble, or Tebrisian marble, after the discovery location near Tebriz. In Australia, there is a deposit of marble onyx in the Beltana Dist., in the southern part of the country. At the European market, the most popular are Pakistan onyx and Algerian onyx. At the American market, the best in quality green Brazilian onyx is supposed to be, it is from Brazil – of the Santana do Matos deposit, Rio Grande do Norte State, and from the Argentina – of a deposit of the San Luis Prov. In Mexico, on the California Penin., Mexican onyx is well-known. It is called also Mexican agate, and its greenish-yellow variety with red veins is called Pedrara onyx; and yellowish-green breccia variety – mosaic agate. In the south of Mexico, in the Pueblo State there are deposits of white Mexican onyx, which is also called Tecalco onyx or Tecali marble.

Synonyms. Aragonite – Chimborazite, after the discovery location near the Chimborazo Mt., Ecuador | Conchite, from Gk. “conche” – tortoise-shell, in the form of plates | Iglite (igloite) | Tecali marble, from Am. Indian “teokali” – a temple | Oolite, syn. oolitic aragonite | Oserskite | Riverstone, Amer. imitation of pearls | ~ spar: Aragon ~, needle ~, pearly ~, satin ~ | Sprudelstein, under the name of source Sprudel (nowadays Vrjidlo in Karlovy Vary) | Alabaster stone | Karlsbad stone, after the discovery location in Karlovy Vary, Czech Rep. (Germ. name Karlsbad) | Pisolitic stone | Ribbon stone | Tarnowskite (tarnowitzite), after the discovery location in dolomites of the Tarnowskie Mts., Poland.

Marble onyx – Calcaire alabaster | Egyptian alabaster | Oriental alabaster | Alabastrite, from Alabastron in Egypt, where a deposit was | Atztec chalchihuitl | Fengite, Pliny the Elder | Mexican jade | Tabriz marble, after the discovery location near Tebriz in the north of Iran | Onychit (onychiy, onychion), Old Russ. | Ophthalmite, eye-like | ~ onyx, from Gk. “nail”: alabaster ~, Californian ~, syn. Mexican ~; Egyptian ~, after a deposit in Egypt; green ~; Java ~, after the discovery location in the region of Javapa Point in Colorado, the U.S.A. | Java ~, from the deposits Kediri near Surabaya (Surabaja), Java Is., Indonesia; Karlyuk ~, after the discovery location in Turkmenistan; Mexican ~, after the discovery location near Pueblo, Mexico; Montana ~, after the discovery location in the Montana State, the U.S.A.; oriental ~, Styrian ~, from the Styria land, Austria; Tyrolese ~, semi-transparent marble, after the discovery location in Laasee, Vintschgau, Tyrol, Austria; Utah ~, after the discovery location in the of Utah State, near Salt Lake City, the U.S.A.; Yaqui ~ | Egyptian quartz | Gibraltar stone, after the discovery location in Gibraltar, Spain.

Ammolite – Iris aragonite | Calentine.

Treatment. From transparent aragonite they receive faceted stones up to 100 ct. for collection purposes. Non-transparent aragonite is processed in cabochons; non-transparent variety is used mainly for stone-carving. In the antique times, marble onyx was of special popularity. It was used for coating in interiors, for stone-carving: sculptures, sacrificial vessels and flasks. It is known that it was extracted even in Mesopotamia in the 5-4 millennium B.C., and later – in Thebes, Egypt. In the tomb of Tutankhamen, they found marvelous vases-lamps from half-transparent marble onyx. In one of the Egyptian pyramids, some thousands of vessels-alabastrons from onyx were found. Relief plates – orthostates from Tabriz marble with carved battle scenes, praising heroic deeds of Assyrian tsars, were used for the decoration of palaces in Mesopotamia in the 9th cent. B.C. In Jerusalem, walls of the Solomon temple were made from this stone. Because of translucency of this stone, there was light even without windows. Aztecs in pre-Columbian America supposed translucent greenish-yellow onyx – Tecali marble to be a sacred stone. They made cult vessels from it. Of the socle of the mausoleum Gur Emir in Samarqand are coated with greenish-yellow translucent onyx. In the State Hermitage, SPb., there is a tabletop with upper part from yellow-brownish aragonite from Czech Rep., 177x88 cm. in size, made at the Peterhof lapidary factory. Onyx is represented also in the decoration of the Gatchina Palace by St Petersburg; there marble onyx is used; besides, there are two tables with upper parts from this stone. In jewelries there are often insets from marble onyx, usually beads and bracelets are made from it.

Legends. In the ancient times, marble onyx was a sacred stone. As an amulet, it protects its owner against fire and madness. On a chalice from oriental onyx in the Uspenskiy (Assumption) Cathedral in the Moscow Kremlin, there is an inscription: “who will drink from it, will be healed”, Christians treat it as a stone of the apostle Philip. Astrologers connect this stone with the planet of Venus. Marble onyx is a lucky stone for those, who were born under the sign of Virgo, and also Capricorn and Taurus.

Similarity. Aragonite looks like calcite, dolomite and other carbonates. Marble onyx can be entangled with serpentinite and ophicalcite.

Barytocalcite (Barytocalcit—Barytocalcite—Баритокальцит) (Kirwan R., 1794), the name reflects its barium content and similarity to calcite. Carbonate – BaCa[CO3]2, monoclinic system. Hardness 4. Density 3.5-3.7. Glass luster to pearl one. Cleavage in one direction. Fragile. It is a rare mineral, which is found in crystals and massive grained aggregates of white, reddish, yellowish and greenish hue. Transparent to translucent. In Russia, on the Kola Penin., at the Khibinskoye deposit, there were findings of its yellow crystals up to 6 cm. In Tadzhikistan, barytocalcite was discovered at several deposits. So, at the Parvinskoye deposit, in the Zeravshanskiy Khrebet, crystals of barytocalcite with transparent segments in their centers reached 30 cm. long; near Kûlob, at the Khermonzhou deposit, in veins among limestone its light bluish-gray crystals with zone coloring form scalloped aggregates; at the Dzhizhikrut deposit they are enriched with inclusions of cinnabar. On Kazakhstan, material available for processing in cabochons was discovered at the Beskempir deposit, on the Mangyshlak Penin., where crystals of barytocalcite contained inclusions of goethite. In South Kyrgyzstan, gem-quality table-shaped, red-brown crystals were found at the Kadamdzhai deposit. In other countries, large crystals of barytocalcite were discovered in Great Britain, at the Alston Moor deposit, Cumbria Co.; and in Germany – near Freiberg, Saxony.

Gaylussite (Gaylussit—Gaylussite—Гейлюссит) (Boussingault J.B., 1826), after Joseph Louis Gay-Lussac (1778-1850), French physicist and later chemist. Carbonate – Na2Ca[CO3]2•5H2O, monoclinic system. Hardness 2.5. Density 1.9. Dull luster. Cleavage in one direction. Very fragile. It is a rare mineral, which is formed in sediments of sodium lakes. Usually it is represented with oblong or flattened crystals. Color: white with yellowish and grayish tones, colorless. Transparent to translucent. Mineral as itself is of no interest, but there are many interesting decorative pseudomorphs on it. Usually, aggregates of gaylussite reach 10 cm. in cross-section and they are replaced with calcite, for instance, in the Russia, in the Arkhangel’sk Region, on the Elva River, in the basin of the Mezen River. Rosette-shaped aggregates of opal pseudomorphs on gaylussite are very beautiful, they are used in jewelry. In Germany, large calcite pseudomorphs on gaylussite occur at Obersdorf, near Sanderhausen, Saxony-Anhalt. In Denmark, similar pseudomorphs up to 40 cm at Lim Fjord are known. In Scotland, near Helensburg, they found crystals of gaylussite up to 10 cm.; as well as in Kenya, near Amboselli Lake. Its type occurrence is Lagunillas, near Mérida, Venezuela. They were faceted for collection purposes, and milky-white massive material was processed in cabochons. On the open air gaylussite is gradually loosing water and growing turbid, that’s why collectors keep it in close vessels.

Ikaite (Ikait—Ikaïte—Икаит) (Pauly H., 1963), after its discovery location on the Ikka Fjord, near Ivigtut (Arsuk Fjord), Greenland. Carbonate – Ca[CO3]•6H2O, monoclinic system. Hardness ~2. It is a rare mineral, which is crystallized under water surface, stable only by 4ºC. At the same time, it is replaced “in situ” with calcite, forming pseudomorphs in the radial-rayed shape up to 30 cm.. They are widespread in many countries of the world, especially on coasts of northern seas, and they are known under different names: fossil pineapples, gennoishi, glendonites, hedgehogs, pseudo-gaylussite, pseudo-pirssonit and others. Sometimes they are used as amulets or in adornments.

In Russia, glendonites are found on the Taymyr Penin., in the valley of the Balakhnya River, where they resemble hedgehogs and are called so – hedge-hogs. They are composed with numerous sharp, light colored crystals not more than 10-15 cm. in cross-section. Glendonites were extracted as an interesting collection material. In the southern part of the Kola Penin., at the Olenitsa River, beside these “hedge-hogs”, White Sea rogulkas (ragoulki) are found, which are characterized with the less complicated shape – a spherical one with small “horns”. Similar glendonites on Bol’shevik Is., North Land Iss., Northern Siberia, were discovered. In Australia, it’s occurred near Eromanga, Queensland; also in New South Wales, near Glendon Brook, after which they were called. The same pseudomorphs on sharp pyramidal crystals of ikaite were discovered in the U.S.A. in cavities of lime tufas of Nevada. There, they are located in coast sediments of quaternary glass Laontan Lake; they were described under the name of tinolite. In other regions, similar formations reached 80 cm. in cross-section.

Synonyms. Hyroconite | Jarrowite, calcite pseudomorphs after ikaite | Natrocalcit.

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