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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

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APATITE


APATITE group (Apatit—Apatite—јпатит) (Lise, 1772). Agroup name, from Gk. “apatao” – to deceive, because of its confusion with other minerals of similar appearance.

Composition & Properties. Phosphate – Ca5[(F,OH,Cl)(PO4)3], hexagonal system. Hardness 5. Density 3.1-3.4. Glass luster to greasy one. Fragile. It is found as table, short- or long-columnar crystals and solid grained masses and radial-rayed aggregates – apatite suns. According the composition, they classify: fluorapatite, chlorapatite, hydroxylapatite, carbonate-fluorapatite – francolite, or kurskite, carbonate-hydroxylapatite – dahlite, manganapatite and mangan-hydroxylapatite. In its pure form apatite is colorless. Transparent to translucent. For colored varieties of apatite soft tones are typical. The admixture of manganese in different coordination produces yellow-green, light blue, blue-green, pink and violet color; the admixture of iron (Fe2+) – smoky one; admixtures of rare-earths, neodymium and praseodymium – yellow one. Pink color, which disappears with the heating up to 600°C and is restored with irradiation, is linked with the admixture of samarium (Sm2+). Significant roles in its color electron-hole centers are playing, which form violet, green, yellow and light blue tones. They classify yellow-green apatite – asparagolithe, green trilliumite, greenish-blue moroxite, light blue Madagascar apatite, or neon apatite. Its light blue variety displays strong pleochroism – from light blue to greenish-yellow to colorless. Intensive lilac-pink fluorescence is observed in yellow apatites, and in light blue ones it is light bluish-violet to pale lilac; green apatites display mustard-green fluorescence. Saturation with inclusions of hematite produces dark red to red-brown hue; inclusions of bioorganic materials make it black. Inclusions of hematite and goethite can produce the effect of cat’s-eye in cabochons of green apatite. Inclusions of lazurite make it blue – lasurapatite.

Dahlite is biomineral according the conditions of its formation, it includes teeth and bones of vertebrates. Collophane is a common name for fine-grained and cryptocrystalline varieties of apatite, represented with concretions, sphaerolites, pseudomorphs on fossilized bones and organic remnants, for instance, odontolite and osteolith. Silicified variety of collophane is called ciplyit.

Ornamental rocks. Phosphorite is a rock of the sedimentary origin, composed mainly with francolite with the content of P2O5 >19.5%. It is usually colored gray or brownish with iron hydroxides and clay minerals. Sea deposits of phosphorites can be represented with fine-grained, nodule and shelly varieties. Continental deposits are represented with wandering forms of apatite in weathering crusts. Polychromatic varieties of these rocks are ornamental stones.

Deposits. Apatite is a typical mineral of granite pegmatites, hydrothermal veins; it is not rare in metamorphic and metasomatic, in alkali syenites, carbonatites and in sedimentary rocks. In Russia, the largest deposits of apatite are situated on the Kola Penin., in the Khibiny massif. There, along with fine-grained apatite, in alkali pegmatites they find crystals of green, blue and violet apatite up to 3x3x10 cm. in size. Sometimes, they are transparent or half-transparent, available for processing. In the Lovozero massif they found yellow-green strontium apatite – saamite in the form of transparent crystals up to 1x1 cm., more rarely up to 12x6x6 cm. in size. In the Murmansk Region, in the zone of oxidation of the Kovdor iron-ore deposit, they find cryptocrystalline greenish-light blue wandering aggregates of francolite, also called Laplandian turquoise. In North Karelia, at the Khetolambina deposit, by the railway station of Chupa, in mica pegmatites, they found crystals of non-transparent apatite up to 10 cm. long. In the Subpolar Urals Mts., apatite is often found in pockets fulfillment of alpine veins with rock crystal. At the deposits Puiva and Central Patok, it was found in the form of transparent flattened crystals of pale green or pale violet color, up to 3 cm. wide and 0.4 cm. thick. The maximum size of pale green crystals at the Dodo deposit reached 18x3 cm. In the Middle Urals, in pegmatites near the village of Murzinka, they find transparent crystals of blue apatite. Its findings are registered also near Nizhniy Tagil, at the Lebyazhinskiy mine; and in the South Urals – at the Rechnoye (Dzhaman-Akzhar) deposit, in the Orsk Dist.; and in Bashkortostan – at the Kiryabinskiy mine, near the city of Uchaly. In Transbaikalia, at the Sludyanka deposit, they found translucent greenish-blue crystals of fluorapatite up to 250 kg. in weight and 1 m. long, but they were only partly available for cut in cabochons. Obvious pleochroism from greenish-yellow to bright blue is typical for them. At the Malo-Bystrinskoye deposit of lazurite, they discovered sky-blue lazur-apatite, which color depended on admixture of lazurite. In Central Transbaikalia, in the Malkhan Ridge, in pegmatites of the Mezenskoye field, they find barrel-shaped crystals of rose and raspberry-red apatite up to 15x20 cm. in size. Because of their transparent segments, they are of interest as gem-quality rough material. In Rep. Sakha (Yakutia), at the Nadezhdinskoye deposit of phlogopite in Aldan they described green crystals of apatite up to 20x15 cm. in size. At the Seligdar deposit they found brick-red apatite. At the Inagli deposit of chrome-diopside, they described findings of strontium apatite in the form of light yellow crystals up to 4x0.5 cm. In Kazakhstan, colorless crystals of gem-quality apatite up to 9 cm. long were found in rock crystal-containing pegmatites at Bektau Ata, Asu Bulak and Akzhailyau. The most beautiful light blue apatite was discovered at the Aqshataü deposit, where its crystals resembling aquamarine formed druses. The biggest druse, 20x20 cm. in size, was called the “Star of Asia” because of its beauty. At the Zhantas deposit, the Karatau Ridge, in greenish-yellow to yellow-brownish phosphorites thick crusts of greenish-white francolite are formed, which resemble marble onyx. In Tadzhikistan, in the West Pamirs Mts., in the region of the Kukh-i-Lal deposit, in miarolitic cavity of oligoclase pegmatites, they found crystals of half-transparent, grayish-green apatite up to 1.5x3.5 cm. In Azerbaijan crystals of apatite up to 12 cm. at the Dashkesan deposit were found. In Georgia, at the Lukhumi deposit, they discovered violet apatite.

In Europe, in South Norway, near Arendal, there are deposits of gem-quality apatite, where they extract greenish-light blue moroxite; near Bamble – chlorapatite, and crystals up to 10 cm. at the Snarum mine, Buskerud. In Germany, occur small crystals of violet apatite in greisens near Ehrenfriedersdorf, Saxony. In Spain, yellowish-green ornamental apatite – asparagolithe, which has also the local name jumillite, at the Sierra de Espuna deposit, Murcia Prov., were found. In Portugal, at the Panasqueira mine, they found table crystals of apatite of flesh and lavender color, up to 10 cm. wide. In Austria, rose apatite up to 5 cm. wide was discovered together with emerald at the Habachtal deposit. Colorless and pale green plate crystals of apatite up to 5 cm. wide are found in Alpine veins of the Knappenwand deposit; and wine-yellow crystals up to 17 cm., with transparent segments, were extracted at the Stubachtal deposit, Salzburg. In alpine veins in Italy, Tyrol, and in Switzerland, it occurs colorless and violet lamellar crystals apatite up to 20 cm. at the Poncione Della Fibbia deposit, Ticino canton. In Czech Rep., short-columnar green to yellow-green crystals up to 5 cm. occurs at Dolní Bory, Moravia; and at Písek, Bohemia (historical region).

In the north of Africa, in Morocco, in the High Atlas Mts., there is the Imilchil deposit, where they extracted transparent crystals of apatite up to 3 cm. in size. The best gem-quality apatites are coming to the market from Tanzania, where its transparent green and purple crystals are extracted at placers on the Umba River. There is also yellow-green apatite cat’s-eye and red-brown apatite there. It is also displays the effect of cat’s-eye in cabochons because of needle inclusions of goethite or lepidocrocite, oriented in parallel to the long axis. In the strength and beauty this gemstone can be compared with the best samples of chrysoberyl cat’s-eye. In Zambia, they extract gem-quality green, bluish-green and sapphire-blue apatite. In Namibia, near Windhoek, there is the Marmor deposit with blue-green apatite, and at the Arandis deposit they find similar crystals of apatite up to 11 cm. wide. In Namibia, large crystals of apatite are found together with heliodor at the Rössing mine. In Mozambique and Kenya, they find mainly green apatite. On Madagascar, findings of light blue apatite crystals up to 40 cm. are known, and in the region of Vohemar – of gem-quality light blue, green and blue-green crystals up to 6 cm. In South-Eastern Asia, on Sri Lanka and in Myanmar, in the region of Mogok, they have extracted transparent light blue and light blue-green apatite at placers since long ago, as well as apatite cat’s-eye. In India, in Rajasthan, in the region of Jaipur and Ajmer, and also in Tamil Nädu, near Chennay (form. Madras), they find bluish-green apatite and yellow-green apatite cat’s-eye. From Pakistan rose and red apatite in crystals up to 20 cm. in size is coming to the market; it is extracted from pegmatites in the territory of India, in the valleys of the Shigar and Khunza Rivers, Jammu and Kashmir (disputed area). In Afghanistan, at the Kereta deposit, Nuristan Prov., they discovered transparent crystals of lilac apatite. In Australia, they find pale blue crystals of apatite up to 10 cm.

In the U.S.A., the biggest findings of apatite crystals were registered. In South Dakota, at the Hugo mine, they extracted an indigo-blue non-transparent crystal of apatite up to 500 kg. In Maine State, at the Mt. Apatite deposit, near Auburn, they found violet and purple crystals up to 25 cm. faceted stones from them were up to 170 ct. A transparent crystal of violet apatite, 3x3.8x4.3 cm. in size, from this deposit is exhibited in the Smiths. Inst., Wash. In New Jersey, at the Franklin deposit, they found crystals of blue apatite up to 9 cm. long. In California, in miarolitic cavity in pegmatites occurs prismatic crystals of gem-quality apatite at the Himalaya mine. Usually, they were colored light rose to thick wine-red or sky-blue to blue. Some of these crystals were polychromatic – rose in the center and blue at the edges. The maximum size of these crystals was up to 7.5x5x5 cm. On Alaska, findings of brown-green apatite crystals up to 10 cm. are not rare. In Canada, they found giant crystals of apatite, that’s why it was established as a national symbol. In the Ontario Prov., at the Lake Clear deposit, Renfrew Dist., they discovered a non-transparent crystal of fluorapatite 300 kg. in mass; at the deposits Bancroft and Harlburton Co., they extract gem-quality green, light bluish-green and olive-green apatite – trilliumite. In the faceted form up to 10 ct., mounted it was evaluated up to $ 1,000 and even more. In the Québec Prov., from the Buckingham deposit in the was 2 m. wide and 250 kg. in mass. There was also the biggest crystal of apatite found – 2.13x1.22 m. in size, 5,443 kg. in mass. In the Yukon Prov. transparent crystals of green apatite up to 2 cm. are found at the Scepter Claims deposit, near Emerald Lake.

In Mexico, occur transparent bright yellow and greenish-yellow crystals of apatite – amarillas at the deposits Serro de Mercado and Mapimi, Durango. However, under heating they can loss their color. From yellow crystals they make faceted stones up to 60 ct., but usually not more than 5-15 ct. In the Sorbonne Univ. Collection, Paris, a yellow crystal apatite up to 5 cm. from Mexico is exhibited. In Bolivia, at the Llallagua deposit, Potosí Dept., they extracted pink to purple and colorless crystals of apatite up to 8 cm. Brazil is known of deposits of gem-quality apatite of different colors. In Minas Gerais, in pegmatite occurs green apatite together with aquamarine at the Campo Lindo deposit. Light blue, green and sometimes rose crystals are extracted at the Morro Velho deposit; and at the Toka da Onka mine, and at the Virgem da Lapa deposit, they extract crystals up to 15 cm.; in pegmatites of Urupuca – gray crystals up to 10 cm. long. They described also transparent olive-green crystals with transfer to light brown, with weak lilac or light gray tones, and also amber-yellow and bright blue apatites, which displayed the effect of cat’s-eye in cabochons. Usually, their size is not more than 10 cm. long, however, at the Tucson jewelry show in 1990, the U.S.A., they exhibited a crystal of apatite from Brazil 100 kg. in mass. In the Paraíba State crystals of fluorapatite from the São José da Batalhya mine, growing on blue elbaite, are especially beautiful, also crystals up to 12 cm at the Alto Feiho are known.

Synonyms. Améthyste basaltine, violet | Saxon amethyst | Strontium apatite | Talc-apatite | Asparagolithe, from Lat. “asparagus”, after its color , and Gk. “litos” – a stone | Augustite (agustite), obs. | Saxon beryl | Common chrysolite | Davisonite, after the Amer. mineralogist J.M. Davison | Peruvian emerald | Estramadurite, after the discovery location near Estramadura, Spain | Mangualdite, after the discovery location near Mangualde, Portugal | Marenit, local name in Pribaikalia, Russia | Moroxite, from Gk. “moroxos” – pipe clay, after its color | Rhodophosphite, from Gk. “rhodon” – a rose, after its color and composition | Saamite, after the people of Saami on the Kola Penin., Russia | Spargelstein | Asparagus stone | Talcum | Tavistockite, after the discovery location at Tavistock Dist., Great Britain, discr. by IMA | Trilliumite, trade name in Canada.

Dahlite, after the Norwegian geologists, brothers T. and M. Dahll – Ciplyit, after the discovery location in Ciply, Belgium | Collophane, from Gk. “colla” – glue and “phainestai” – to seem | Francolite, after the discovery location near Will Franco, Tavistock Dist., Great Britain | Jumillite, after the discovery location near Jumilla, Prov. Murcia, Spain | Phosphorite, from Gk. “phosphorus” – giving light, the initial name of apatite, which became the name of a rock | Staffelit, after the discovery location near Staffel, Hessen, Germany.

Treatment. In spite of diversity of colors of apatite, it is not one of the well-known gemstones because of its low hardness. Meanwhile, we can find it in many museums and private collections. In the U.S.A., in Maine State, collectors possess a purple apatite up to 1.5 ct.; in Brazil – a blue one 2 ct.; in Myanmar – one looks like aquamarine up to 10 ct.; in Mexico – a yellow one up to 25 ct. From green apatite they make the biggest faceted stones up to 100 ct. Yellowish stones with the effect of cat’s-eye usually are not more than 15 ct., and green ones with the same effect – 20 ct. Non-transparent and translucent apatites are cut in cabochons and used in stone-carving. The biggest faceted green apatites from Kenya reached 147 ct., and apatite cat’s-eye – 207 ct. In the Smiths. Inst., Wash., there is two apatites 29 ct. each one – a yellow one from Mexico and a yellow-green one from Mogok, Myanmar; and also a blue apatite from Sri Lanka – 8.8 ct. In the Museum Hist. Nat., Paris, there is a green apatite from Brazil 31.4 ct.

Synthesis. Apatite of green hue with bright yellow tone, resembling chrysolite. Synthetic apatite produced for jewelry purposes. From other synthetic phosphates as gem-quality material synthetic gadolinium yttrium phosphate can be used.

Similarity. In the faceted form apatite looks like amblygonite, andalusite, beryl, brazilianite, titanite, topaz, tourmaline and chrysoberyl.

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