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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

LAZURITE, GROUP: LAZURITE, AFGHANITE, BYSTRITE


LAZURITE group (Lazurit—Lazurite—Ћазурит) (de Boot, 1647 in Brögger, W.C. & Bäckström, H. 1890), from Arabic “lazauward”, Persian “lazhuward” – blue, or from Lat. “lazulum”, after its color. Here also afghanite and bystrite are described – also framework silicates, which are found as significant admixtures in lazurite rock – lapis lasuli.

Composition & Properties. Lazurite – (Na,Ca)8[S2|(AlSiO4)6], silicate, subclass framework silicate, cubic system. Hardness 5-6. Density 2.5-3. Glass luster to dull one. Fragile. Lazurite is found mainly as grained masses, crystals are rare. They are isometric 12-faced in shape, not more than 2 cm., rarely up to 5 cm. Non-transparent to translucent. Color: blue of different tones, violet, raspberry-red, greenish-blue, yellow and pink. It depends on molecular ions of sulfur in the content of the mineral, which produce centers of stable color. The name lazurite is also used for the rock containing this mineral, and in Western gemology this rock is usually called lapis lazuli. In the content of the rock there is lazurite – up to 25-40%, and besides – diopside, calcite, potassium feldspar, micas, also there can be admixtures of haüyne, nosean, sodalite, pyrite, amphiboles and pyroxenes. At some deposits, ,lapis lazuli contains admixtures of wollastonite, afghanite and bystrite. Lapis lazuli is also the trade names for azure, azul and lapis matrix. The commercial value of lapis lazuli is in direct proportion to the content of the mineral lazurite and depends on the evenness of color and texture of the rock. The most expensive is even dark blue lapis lazuli with insets of small pyrite up to 10-15%, so called golden sapphire. Material of low quality with light color is lapis lazuli with admixture of calciteblue zeolite.

Deposits. Lapis lazuli was formed in the process of metasomatism of carbonate rocks near contacts with granitoids and gneisses. The main deposits are situated in Russia – by Baikal Lake, in Tadzhikistan – in the West Pamirs Mts., in Afghanistan – in the Badakhshan Prov., in Chile – in the Andes. In Russia, lapis lazuli was discovered in boulders on the Slyudyanka River, to the southwest from Baikal Lake. In 1786, E. Laksmann, who visited those places, sent the first 20 poods (about 320 kg.) of lapis lazuli to St Petersburg, to the Peterhof lapidary factory. In 1851-1865, G.M. Permikin discovered seven base deposits of lapis lazuli in marbles and calciphyres on the rivers Slyudyanka and Malaya Bystraya, in the spurs of the Khamar Daban Ridge. For the first 20 years they have extracted here 2,110 poods (34 tons) of lapis lazuli. Industrial resources of lapis lazuli are concentrated mainly at the Malobystrinskoye deposit, 55 km. to the southwest from Slyudyanka, Irkutsk Region. From 1966 till 1990, they extracted 241.3 tons of quality rough materials there. Lapis lazuli from this deposit differs from Badakhshan lapis lazuli with ink tone of its violet-blue color. The output of gem-quality material is not high, mainly there is ornamental stone with the content of lazurite from 20 to 50%. Beside isotropic lazurite of cubic system, they discovered there its anisotropy variety of triclinic system with pleochroism from pale blue to colorless. Besides, a monocline varieties was discovered, which is found together with blue-violet glaucolite – afghanite and bystrite. Along with the Malobystrinskoye deposit in that region there are other deposits of lapis lazuli of practical interest: the Sliudyanskoye and Tultui. Recent years, in the East Sayan Mts., they discovered a new region of findings of lapis lazuli in the basin of the Urik River.

In the Ukraine, lapis lazuli was found out in the Carpathian Mts. in 1966; there was the Rakhovskiy massif in the region of the Delovetskiy marble career. Lapis lazuli of bright cyan color forms jacks in calcite-diopside rock. Sometimes, it contains inclusions of the pyrite. In Tadzhikistan, in the West Pamirs Mts., the Lyadzhvar Dara deposit of lapis lazuli was discovered in 1930. It has been known by legends since the deepest antiquity. In 1271, Marco Polo wrote about the lazurite mines of Badakhshan region. It is situated 60 km. to the southeast from Khorugh, at the level of approx. 5000 m.; it is an analogue of famous Afghan deposits of the Badakhshan Prov. Lenses of lapis lazuli, not more than 2x6 m. in size, are deposited there in forsterite marbles; there are industrial resources of jewelry-ornamental rough material there. In Afghanistan, there is the most ancient and the largest Sar-e-Sang (Sary Sang) mine of lapis lazuli. It is situated in the Badakhshan Prov., 70 km. to the southeast from Faisabad, at the level of 3000-4000 m. Its area is about 2 km2. There, in a layer of magnesia marbles and calciphyres they extracted blocks of lapis lazuli up to 100 kg., and crystals of lazurite reached the size of 5 cm. In the composition of lapis lazuli there is diopside – up to 60%; scapolite, haüyne, afghanite – up to 10-25% in general; and pyrite – up to 2 %. In spite of significant scales of the deposit, extraction is limited – the volume is not more than 1 ton per year. From the general output, gem-quality material is not more than 2%. Afghan lazurite is classified in such sorts: “niili” (Pers. blue) – of thick blue color; “asmani” (Pers. sky) – of bright light blue color; “sufsi” or “sebtsii” (Pers. green) – of greenish-blue color. Badakhshan lapis lazuli, as well as Pamir lapis lazuli, is polished better, because its light colored admixture is represented with harder diopside, and in Baikal lapis lazuli – with mild calcite. Besides, in the same Badakhshan Prov. of Afghanistan, there are smaller deposits of Afghan lapis lazuli. In Italy, lapis lazuli was found at the Monte Somma deposit, in Vesuvium, and in the Albani Mts., Lacio Prov. Besides, findings of lapis lazuli are known in Turkey, Pakistan, South Africa, Angola and Rwanda. In India, in the Jammu and Kashmir State (disputed area), there is the Guläbgarkh deposit of lapis lazuli; in area Skardu; and in the Madhya Pradesh State – the Bhandra deposit. In Myanmar, lapis lazuli was extracted in the valley of the De Taw River, near Mogok.

In Chile, in the Andes, there are several deposits of lapis lazuli in the Prov. Antofagasta, Atacama, Coquimbo and Santiago. The main of them is the Carén deposit in the Coquimbo Prov., to the east from Ovalle, at the level of 4,500 m., in the source of the rivers Cazadero and Vias, tributaries of the Rio Grande River. All the deposits in Chile are deposited in marbles, containing small insets of lazurite, veins and rare accumulations of Chile lapis lazuli up to several kilograms in mass. However, in one of the tombs they found a block of lapis lazuli 20x30x61 cm. in size. Color of lapis lazuli is pale to light blue, often with green tones. In its composition there are veins of calcite, inclusions of wollastonite and pyrite. In the U.S.A., there are small deposits of lapis lazuli. In California, there is Ontario Peak, Cascade Canyon and the Beegorn Mine in the San Gabriel Mts. In Colorado, there is the Blue Winkle mine; and in Wyoming, findings of lapis lazuli are connected with rocks of the formation Green River. In Georgia, at the Graves Mountain deposit, crystals of lazurite, up to 3.5 cm. wide, were found. In the New York State, lapis lazuli was found only in small quantities at the Balmat area, St Lawrence Co.; and at the Edwards mine, in dolomite marble, they discovered a massive isolation of lapis lazuli, 3x1 m. in size. In Canada, in the south end of the Baffinland, 15 km. to the north from the Harbour Lake, in marbles, they found the deposit of lapis lazuli of the same name. Only one part of it takes the area of 3,500 km2. Accumulations of pale blue lapis lazuli are up to 1 m. wide. In the content of lapis lazuli the main mineral is diopside – 40-60%, and lazurite is not more than 40%. Lazurite also was found in Brazil on deposits Dattas, Serra do Espinaso and Tijuco, Minas Gerais.

Synonyms. Arminakun, obs. | Azurite (azurium), by mistake | Berlinerblau, Germ. | Blauspath, Germ. | Chile lapis | Chin-chin-shih, Chinese | Cyanus (Kyanos, Lat.) by Theophrastus (372-287 B.C.) | Scythian cyanus | Blue feldspar | Khesbet, anc. Egypt. | Klaprothite, after the Germ. mineralogist M. Klaproth | ~ lapis: copper ~, false ~, German ~, Khorong ~, Matrix ~, Swiss ~| Lazuard, Arab. | ~ lapis lazuli (Lat. “lapis” – stone and Arab. “azul” – blue): Afghan ~, Baikal ~, Colorado ~, Khorong ~, by mistake, after Khorugh (Khorog), in the Pamirs Mts., Nevada ~, oriental ~, Russian ~, syn. Baikal lapis lazuli, sometimes also Badakhshan lapis lazuli, when it was exported through Russia; Siberian ~. | Lazulite, by mistake | Lazurik, Old Russ. | Lazurium, obs. | Lazurstone | Blue malachite | Blue opal | Sappheiros, Lat. (sapphirus), by Theophrastus (372-287 B.C.), obs. | Sapphirine, obs. | Blue spar | Lazur spar | Armenian stone | Azure stone | Bokhara stone | Swiss stone | Blue zeolite.

Quality improvement. Since the ancient times, the identity of lapis lazuli was checked with annealing, under it the color is strengthened because of the transformation of Sulfate group Sulfur to sulfide one. Low quality lapis lazuli with big quantity of light colored minerals sometimes is improved with an artificial painting of its polished surface in ready-made produce.

Treatment. Lapis lazuli has been known for more than 7,000 years. In the ancient states of Mesopotamia and in Egypt, they adored amulets from lapis lazuli cut in the shape of scarabs. They decorated symbols of authority – pectorals. Such pectoral in the shape of carved griffon with extended wings was found in the tomb of Tutankhamen. Birds feathers were made from 256 movable gold plates decorated with lapis lazuli, red jasper, turquoise and obsidian. This pectoral is kept in the Cairo Museum. In a tomb of Pharaohs of the Middle Kingdom (11th cent. B.C.), they discovered a unique “Necklace of Psusemnes I” from lapis lazuli. It is kept in the Louvre, Paris, France. An honorary sign of the Supreme Judge of Egypt was a figure of the goddess Maat cut from lapis lazuli. In ancient tombs, they discovered cylindrical stamps, balls, carved figures of animals and birds from lapis lazuli. According a legend from the Bible, the Decalogue was written on ten tables from lapis lazuli. Over the throne of the Iran Shah Khosrov II, there was a canopy from lapis lazuli and gold. In China, balls from lapis lazuli served as symbols of official dignity; they decorated headdresses of the Emperor and the highest dignitaries. In Tibet, lapis lazuli was in a special demand among lamas, who evaluated it higher than gold.

In the 17-18ss cent., Badakhshan lapis lazuli was taken to Russia with caravan through China; it was valued as silver. In spite of this fact, when O. Monferrant didn’t like dark Baikal lapis lazuli for coating of 5 m high columns of the altar of St Isaac’s Cathedral, he changed it with brighter Badakhshan lapis lazuli. This stone was widely used in the decoration of tsars’ palaces in St Petersburg. In the State Hermitage, there are several tables and vases from lapis lazuli, including the biggest two, 172 cm. high. There is also a vase from a whole block of lapis lazuli, 24 cm. high and 18 cm. in diameter. In Tsarskoye Selo (now the city of Pushkin), in the Lyonnaise hall of the Catherine Palace, there are several things made at the Peterhof lapidary factory from Baikal lapis lazuli: four tables, a chandelier, two fire-screens and two frames for mirrors. Vases and other big work of art from lapis lazuli, as well as the same from malachite, were manufactured with the method of “Russian mosaic” (See malachite). Besides, this method was used in the coating of the lower part of the hall and in the plat bands. Baikal lapis lazuli was used in the decoration of the Spanish hall of the State Hermitage, SPb. There are also two vases and two tables from Badakhshan lapis lazuli and a pair of vases from Baikal lapis lazuli. In the collection of gems, several cameos on lapis lazuli are represented, including one with three Graces, Italy, 16th cent., and 2x1.8 cm. In a monumental work of the Soviet period – the mosaic “Map of the U.S.S.R.” lapis lazuli of different tones was used for the depiction of lakes, seas and the Polar Ocean.

In Europe, lapis lazuli as a rare and precious stone and as a coloring component of ultramarine, has been known since the 5th cent.. Till 1704, it was sold at the price of gold, before two dyers from Berlin discovered by chance a composition of iron, which gave dark blue color; it was called Berlin lazur. Later, ultramarine was received artificially, alloying kaolin with soda and sulfur in the presence of coal as a reducing agent. In the epoch of the Renaissance, lapis lazuli was used in significant quantities for incrustations in the Florentine mosaic and in manufacturing of adornments and ornamental produce. In Florence, in the Palazzo Pitti, there is a vase from lapis lazuli, 40.5 cm. high. Lapis lazuli was used as a sincerity stone and a sign of deep friendship in diplomatic gifts. Such gifts of the Russian Emperor to the German Kaiser Wilhelm I in 1873 were several vases from lapis lazuli and a silver copy of a monument of Peter the Great on a pedestal from of lapis lazuli.

Legends. Since the deepest antiquity, they have attributed unusual properties to lapis lazuli. In Ancient Rome, it was supposed to be an aphrodisiac. In the Middle Ages, they believed that it healed eyes and skin, made a body younger, took away high fever and head-ache. As an amulet, it protects against gloomy thoughts and spleen. As a talisman, it strengthens friendship and love, helps to get a success and to make a spiritual discoveries. For those who are born under the sign of Libra it reduces their weak points – the lack of patience, mutability in love and friendship. Astrologers use it for the stimulation of an organism, strengthening of a physical body and conscience. Lapis lazuli is a lucky stone for those who were born under the sign of Aquarius, Aries, Virgo, Libra and Sagittarius. Shappir – the fifth stone in the breast-plate of the high-priest was obviously lapis lazuli. Lazurite is regard as a national symbol of such countries as Chile, Bolivia and Bukhara in Central Asia (now Badakhshan on Pamirs Mts.). In Canada, lapis lazuli is an official emblem of the. Yukon Prov.

Synthesis. In 1974, the firm of P. Gilson received Gilson’s lapis, or synthetic Gilson’s lapis lazuli. It is manufactured from a powder of synthetic ultramarine with addition of water zinc phosphates, with the method of agglomeration into solid aggregate together with crystals of pyrite or without them. It is dark blue, slightly porous material without admixtures of resins. Its mineralogical characteristics are closer to sodalite, than to lazurite. Meanwhile, it can be classified as an imitation. They received artificially synthetic sodalite replacing chlorine with bromine, barium and lithium. Under annealing with H2S it transfers to lazurite. Besides, they synthesized ultramarine of the content Me(AlSiO4)6S2-1, where Me = barium, silver, potassium, thallium, strontium, zinc, manganese, and lead. Instead of sulfur, they can use also selenium. Ultramarine, from Lat. “ultra” – over and “marinus” – a sea.

Similar Gemstones & Imitations. Gemstones resembling lapis lazuli are azurite, dumortierite, lazulite, and sodalite. Blue color was popular in adornments of the East, and because of the lack of expensive lapis lazuli they replaced it with blue enamel or glassastralith. Since the 3rd cent. B.C., they have manufactured blue cobalt glass to make beads. White spots, typical for lapis lazuli, were represented in glass with cristobalite. For the imitation of blue lapis lazuli with inclusions of pyrite they used blue aventurine glass with crystals of copper. In Germany, there was an imitation of lapis lazuli – Swiss lapis, or German lapis from Nunkirchen jasper, colored with Berlin lazur. In 1954, in Frankfurt-upon-Main the firm “Degussa” invented the first synthetic imitation of lapis lazuli from polycrystalline aggregate of agglomerated synthetic spinel with admixture of pyrite or gold. Cheaper imitation is reconstructed lapis, which consists of fragments of marble, processed with Copper Sulfate group and cemented with resin with admixture of pyrite. One more imitation is grids of lapis lazuli, cemented with plastic with admixture of pyrite. As material for imitations, they use barium phosphate with binding components, and also paint howlite, pyrophyllite and chalcedony.

Afghanite (Afghanit—Afghanite—јфганит) (Bariand, P. et al. 1968). The name is derived from the country of its discovery Sar-e-Sang, Kokcha Valley, Badakhshan Prov., Afghanistan. Silicate – (Na,K,Ca)6Ca2[(SO4,CO3)2|(Cl,OH)2|(Al,SiO4)6]·nH2O, hexagonal system. Hardness 5-5.5. Density 2.5. Glass luster, greasy one. Cleavage imperfect, in one direction. Fragile. According its composition afghanite takes an intermediate position between sodalite and cancrinite. It was discovered in lapis lazuli from Afghanistan, and later it was found at the main part of other deposits of lapis lazuli; and in Italy, at Casa Collina, near Pitigliano, Tuscany. It serves as a rock-forming mineral along with lazurite, and sometimes replaces it. Its content in lapis lazuli can reach 50% of general volume. It is represented with small plate crystals up to 4 cm. long or with columnar aggregates in tight accretion with lazurite, diopside and calcite. Sometimes, it forms accumulations of an isometric shape. Color: light bluish-green, more rare light blue, sometimes colorless. Thick colored varieties display pleochroism from pale blue to colorless. The nature of its color is the same as in lazurite. Under partial transformation it gets brownish or foggy.

Bystrite (Bystrit—Bystrite—Ѕыстрит) (Sapozhnikov et al., 1991), after its discovery locality, at the Malo-Bystrinskoye deposit, Pribaikalia, Russia. Silicate – (Na,K,Ca)8[S1.5|H2O|(Si,Al)12O24], trigonal system. Hardness 5. Density 2.5. Glass luster. Cleavage in one direction. It was discovered iin Russia, in lapis lazuli of the Malo-Bystrinskoye deposit, Pribaikalia in 1976, there it was represented with small plate crystals up to 5 mm. long and their aggregates. Color: yellow, in accretion with lazurite – greenish. Non-transparent to translucent. Under partial transformation it gets brownish. After the annealing in the open air up to 800°C, it becomes green. It presents in lapis lazuli as afghanite. Usually, it is developing on lazurite, sometimes replacing it more than in half and forming lazurite-bystrite-diopside rock, containing up to 15-20% of bystrite.

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