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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

TEKTITE, GROUP: TEKTITES, IMPACTITES, METEORITES


TEKTITES group (Tektite—Tektites—“ектиты) (Zuss, F. 1900), from Gk. “tektos” – fused. Here also impactites – crater glasses of strike origin are described, as well as fulguritesglasses, formed with thunderbolts; and also meteorites.

Composition & Properties. Tektites are usually meteoric glasses – natural silicates of the content: SiO2 60-80% with the small quantity of H2O. They are surely classified as cosmolites, rocks of cosmic origin. Hardness 5-6. Density 2.4. Amorphous. Viscous. Tektites are characterized with the diversity of shapes and places of depositing. Color: green, brown to black. Non-transparent to translucent. Shape: spherical, conic, disc-shaped to lamellar, tear-shaped, dumbbell-shaped. Their size can be from several mm to several cm; the biggest registered weight was 65.7 kg. A typical feature is their fluidal structure and numerous inclusions of liquid and gas bubbles, glass and iron-nickel balls. The sculpture of the surface of tektites is complicated, with traces of melting. Among natural glasses, there are also volcanic glass (See obsidian) and quartz glass, which is formed from strikes of thunderbolts to sand – fulgurites. The last ones are usually crusts or glassy tube bodies, dendrite at the ends – thunderous arrows. They are often transparent, slightly colored, with inclusions of bedding rocks. Fulgurites can reach 1.5-2 m. long with the diameter up to 6 cm., and sometimes even more. They consist mainly of SiO2 and they are represented with lechatelierte. According the calculations, every year about 3.1x1010 thousand of such “arrows” are formed. Sometimes they are taken for meteorite glasses, as it was with Libyan glass. They are used for manufacturing of adornments and amulets. Lechatelierte are produced artificially, too.

Deposits. The age of tektites from different parts of the Earth, calculated with the potassium-argon method, varies from 0.63 to 34 million of years. There are different hypotheses on the source of their substance. They are called after their discovery location. In South Germany, in the region of Dresden, they are called moldavites after the Moldau River, a German name for Vltava, and in Czech Rep. they are called vltavites. In 1788, they were described at first near Loçenice, South Bohemia, in the basin of the Vltava River. Till now more than 40,000 examples were found there. The age of moldavites is 15-20 million of years. They are transparent, green or brown-green glasses, sometimes more than a dove’s egg in size. A unique sample was a roundish moldavites 153 gm., 72x50x45 mm. in size, but in Moravia they found bigger stones up to 258.5 gm.

The following on time were discoveries of tektites on the Tasmania Is. – tasmanites, and later in Central Australia – australites, to the north from Alice Springs, Northern Territories. Their age is 0.68-0.76 million of years, density is 2.31-2.51. Local tribe has knowing them for long. They used them as amulets in healing practice. The general quantity of findings of australites is valued in 10 million; the weight of some samples is from 0.15 to 280 gm. In the end of 1870-s, in Indonesia, during the extraction at cassiterite placers they discovered tektites of green color. At first they were taken for black diamond. Then, in 1898, similar glasses were found on the Bunguran Is., near the Borneo Is. (now Kalimantan), on other islands in Indonesia, and later on the Malay Penin.. All these findings were called billitonites. The biggest of them was 750 gm. Aboriginal people guessed the non-earth origin of those glasses, that’s why they called them moonstones, lightning stones, thunder stones. In West Africa, black tektites, or ivorites were discovered in the Fr. colony Ivory Coast (now Rep. Côte d’Ivoire). Coast Ivory tektites look like moldavites, and they resemble philippinites in color and character of the surface. There are about 200 examples, their age is 1-2 million of years.

On the Philippines Archipelago, tektites were discovered in 1926. At first, they were called rizalites, and later they received a separate, general name – philippinites. They collected more than 500,000 samples, the weight of the biggest one was 1070 gm. Their age is 0.68-0.73 million of years. Local population used philippinites as magical means and called them “taeng-kulong”, “taeng-bituin” – excrements of thunder or stars, and also sunstones or termites stones. In 1941, on the Java and Kalimantan Iss., they discovered javaites. Their general quantity is more than 10,000 examples now, the biggest one is 740 gm., and their age is 2.4 mal of years. Simultaneously with philippinites, in the territory of Thailand, Cambodia, Laos, Vietnam and South China, including the Hainan Is., they discovered black glasses of Indochina – indochinites or Thailandites with the age of 0.63 million of years. The most imposing collection is kept in the Museum Hist. Nat., Paris, where the biggest sample is 67.5 kg. In Laos, they found a tektite 3.2 kg. in mass. In China, Guangdong tektites and Tibetan tektites are known. They were found also in Mongolia, where they were popular as magical stones, being used to call rain. In 1936, in the U.S.A., in Texas they discovered black – bediasites with the age of 33-35 million of years. The biggest one was 91 gm. Then, tektites were discovered in Georgia, where they were called at first empirites, and later georgiatites. Their age was beginning as 34 million of years. Earlier findings in Peru and Colombia, so called americanites, including transparent columbianites, were classifies as volcanic glasses. The latest finding of tektites – jamanshynites was made in Kazakhstan, between the Mugojary Range and the Aral Sea, in the valley of the Yrghyz River, near the Zhamanshin Meteorite Crater, with the crater 5 km. in cross-section. In the region of this crater, they find plenty black and yellowish porous glasses up to 3 cm. in size, with glistening surface and traces of rotation – so called irgizites. Their concentration in bedding rocks is up to 100 examples /m3.

Synonyms. Meteorite glasses: ~ glass: crater ~, desert ~, Libyan ~, meteorite ~, open pit ~ | Bottle stone | Tagamit, rock, composed up to 60% with polymineral glass | Zujwite (süevit), rock, melted in meteoritic crater.

Moldavites: ~ chrysolite: Bohemian ~, false ~, water ~ Pit glass, pebble | Pseudochrysolite.

Australites: Obsidian bombs | Black fellow’s button | Obsidian buttons | Darwin glass, after the discovery location in the mountains near Darwin, Northen Territory Australia | Obsidianites | Queenstownites, after the discovery location near Queenstown, West Tasmania | Tasmanites, after the discovery location on Tasmania.

Billitonites, after the discovery location on the Biilitung Is. (form. Billiton) in the Javanese Sea – Javaites, after the discovery location on the Java and Kalimantan Iss., Indonesia | Malayasites, after the discovery location in Malaysia, or malaysinites, after the discovery location on the Malay Archipelago | Fire pearls.

Philippinites, after the discovery location on the Philippines Archipelago – Indochinites, after the discovery location in Indochina | Rizalites, after a local tribe.

Coast Ivory tektites – Ivorites, from “ivory”.

Bediasites, after a local Indian tribe in Texas, the U.S.A. – Empirites, after the discovery location in Empire Co., Georgia, the U.S.A. | Georgiatites, after the discovery location in Georgia, the U.S.A. | Uruguayan glass.

Fulgurites, from Lat. “fulgur” – a thunderbolt, after the origin, syn. astraphyalites, obs. | Libyan glass | Quartz glass | Silicon glass | Lechatelierte, after the Fr. chemist H. Le Chatelier | Libyanite (livit), after the discovery location in Libya | Devil stone | Lighting stone | Lighting tube | Sand tube.

Treatment. Transparent and translucent varieties of tektites have been used for manufacturing of adornments, mainly beads and pendants, as well as amulets since long ago. Besides, they are valuable as collection material. Moldavites are especially popular in Czech Rep., where they are treated as a national gemstone. The biggest and transparent stones are faceted. Faceted stones up to 20 ct. are known. Such moldavites, mounted in platinum and framed with brilliants and pearls, was gifted by the prince of Edinburgh to his bride, the queen to be of Great Britain Elisabeth II. Billitonites were used for imitation of black pearls under the trade names Negro buttons or fire pearls.In Indochina, polished tektites are not rarely can be observed in sculptures as eyes of Buddha.

Some americanites, tasmanites, skanit or shonites from Sweden and Kerulenic pseudo-meteorite from Mongolia are classified as pseudo-tektites – glassy forms, which affiliation with tektites is not established.

Legends. Astrologers believe tektites are lucky stones of those, who were born under the sign of Gemini. In the U.S.A., they are an official symbol of Oregon.

Similarity. Tektites look like obsidian, jet, smoky quartz and morione.

Impactites (Impaktite—Impactites—»мпактиты), from “impact”, they are classified as cosmolites, natural glasses of strike origin. Among impactites, there is full of bubbles, glassy or fine-crystalline natural material, formed under the falling of meteorites. It was removed as a result of melting of rocks and the substance of the meteorite itself. It differs from tektites with more complicated mineral content. Impactites usually are found in the regions of large meteorite craters – crypto explosion structures (astroblems), which quantity on the Earth is more than 150. The largest one is Sudbury, 250 km. in cross-section in Canada. In Germany, there is the meteorite crater Ris, Bavaria, 25 km. in cross-section. In Russia, the Karskaya cryptoexplosion structure (astrobleme), 60 km. in cross-section, is situated on the south-west shore of the Baidaratskaya Bay of the Karskoye Sea, and the largest one – Popigaiskaya cryptoexplosion structure, more than 100 km. in cross-section, – in the north of the Krasnoyarsk Region. Perhaps, a sample of impactites is the famous “Black Stone” – a Moslem sacred object, which is kept in Kaaba, Mekka. Nowadays, it is placed in a massive silver frame; its visible part is about 36 cm. wide. It was found, presumably, at the astrobleme Vabar in Saudi Arabia.

Material of impactites, as well as those of tektites, is used in manufacturing of amulets and adornments. An artificial analogue of impactites is glassy material – trinitites, formed in the places of explosions of nuclear bombs. Atomic impactites are characterized with high radioactivity.

Meteorites (Meteorite—Météorites—ћетеориты), from Gk. “meteÿros” – lofty, modern Lat. “meteorum”. Cosmic bodies, which fell to the Earth. Their age is about 4.5 biln years, as the age of the Solar system. Every year more than 1000 tons of meteorites fall to the Earth. The most parts of them are burning in the atmosphere. The weight of separate meteorites, fallen to the Earth, varies from several gram to dozens of ton, and 92% of them are stony meteorites, 2% – stony-iron meteorites and 6% – iron meteorites – cosmic iron. Among stony meteorites, or aerolithes the widespread are chondrites, composed with roundish grains – “chondrules”, which were formed under the crystallization of the substance of meteorite. In their content olivine dominates – from 25 to 60%, then pyroxenes: hypersthene and bronzite – from 25 to 35%, nickel iron – kamacite and taenite – from 8 to 21% and even plagioclasemascelynite up to 10%. In stony meteorites – achondrites there are no “chondrules”. In the Novo-Urey achondrite which had fallen in Mordovia, Russia in 1886, for the first time, they have discovered an inclusion of meteorite diamond. Iron meteorites, or siderites are composed on 98% from nickel iron: kamacite with 6-7% of nickel and taenite with 30-50% of nickel. Plates of kamacite are placed in four directions, as if according the planes of an octahedron, that’s why such meteorites are called octahedrites. If you cut octahedrite and pickle them with acids, a typical pattern will be observed – a system of intersected stripes, so called Widmanstätten figures. They were called after A. Widmanstätten, who discovered them in 1808. More rarely iron meteorites – hexahedrites and ataxites don’t possess such texture. In the iron meteorite Canyon Diablo, found in the U.S.A., in Arizona in 1891, they discovered transparent diamonds about 0.5 mm. in size. Stony iron meteorites, or siderolites are of the intermediate content. They are separated into two groups: pallasites, at which the metal fraction cements silicates, and mesosiderites, where, just the opposite, silicates cement iron. Atypical characteristic of meteorites is the presence of numerous small pits and melting crust on the surface.

Synonyms. Dicksonite, after the discovery location in Dickson Co., England | Kamacite (nickel-iron), 5-7% nickel, (K. von Reichenbach, 1861), from Gk. “kamas” – girder, because of Widmanstätten figure, syn. balkeneisen, Germ. | Pallasites or Pallas iron – meteorite, after the Russ. researcher P.S. Pallas (1741-1811), which was found by him in area of Krasnoyarsk, Russia. | Taenite (nickel-iron), 27-65% nickel, (K. von Reichenbach, 1861), from Gk. “taenina” – band, for a platy structure.

Treatment. Meteorite iron has been attracting attention of humans since the deepest antiquity. That time on, people learnt to produce the first forged tools and weapons from it. In Ancient Egypt, adornments from iron meteorites were evaluated higher than gold ones. During the excavations in the region of Gizah, they found beads from forged plates of meteorite iron, made not earlier than 6,000 years ago. On the territory of modern Iraq, amulets and adornments from meteorite iron were discovered in the tombs of the ancient city of Ur. In Ancient Rome, wedding rings from meteorite iron were used. In pre-Columbian America, Aztecs possessed tools and adornments from meteorite iron. A ruler of the Indian princedom Jekhangira had two sabres, a dagger and a pike-head from meteorite iron. Nowadays, collecting of balls made from the substance of meteorites has come into fashion. They manufacture adornments and amulets from them. In the Smiths. Inst., Wash., the U.S.A., they keep a signet “Taxon” with an inset from meteorite.

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