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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

SODALITE, GROUP: SODALITE, HAUYNE, NOSEAN


SODALITE group (Sodalith—Sodalite—Содалит) (Thompson, T. 1810). The name reflects its sodium content. In this group there are haüyne and nosean, with which sodalite forms rows of constant mixing. Silicate – Na8[Cl2|(AlSiO4)6], subclass of carcasses silicates, cubic system.. Hardness 5.5-6. Density 2.1-2.4. Glass luster to greasy one. Cleavage in one direction. Fragile. Sodalite is usually found as massive grained aggregates, filled with white veins of calcite, more rare as isometric crystals. Color: colorless, white, light blue to dark blue, green, reddish. Transparent to nontransparent. As ornamental varieties there are known light blue allomite and pink hackmanit. Color of hackmanit depends on admixture of sulfur, it is unstable, and in the direct sunlight it comes into light bluish or gray.

Haüyne (Hauyn—Haüyne—Гаюин) (Brunn-Neergard, T.C. 1807), after the Abbé René-Lust Haüy (1743-1822), a founder of the science of crystallography; professor, Museum Hist. Nat., Paris. Other names dolomian and ajuin. Silicate– (Na,Ca,K, )8[(SO4)2|(AlSiO4)6], subclass of carcasses silicates, cubic system. Hardness 5.5-6. Density 2.4-2.5. Glass luster, greasy one. Cleavage in one direction. Fragile. Haüyne is found as melted isometric crystals, and more rare as grained masses. Transparent to non-transparent. Color: bright blue, greenish-blue, green, red, yellow. Haüyne is a part of alkali effusive and metasomatic rocks; it exists in the composition of lazurite rock.

Nosean (Nosean—Noséane—Нозеан) (Klaproth, 1815), after Karl Wilhelm Nose (1753-1835), a Germ. mineralogist of Brunswick, who originally described the mineral. Silicate – Na8[SO4|(AlSiO4)6], subclass of carcasses silicates, cubic system. Hardness 5.5-6. Density 2.4-2.5. Glass luster to greasy one. Cleavage in one direction. Nosean in properties is similar with sodalite, haüyne and lazurite, it is usually found with them and sometimes it is taken for them by mistake. Similar to haüyne it is found as melted isometric crystals. There are no separate deposits of this ornamental stone.

Deposits. Sodalite is formed in effusive alkali rocks, syenites and alkali pegmatites. In Russia, it is found on the Kola Penin., in Khibiny and Lovozero alkali pegmatites massifs, as crystals of hackmanit, up to 3x2x2 cm. in size, and monomineral stockwerk up to 3x4 m. In the South Urals, findings of jewelry-ornamental sodalite are known in the region of Miass, in alkali pegmatites of the Ilmeny Mts. In Siberia, in the Krasnoyarsk Region, blue sodalite-containing ornamental rock was discovered in Kiya-Shaltyrskiy massif of Kuznetsk Alatau; in Tyva – in the Sangilen Ridge, in Dakhu-Unur massif; at East Sayan Mts. – in Botogol locality, at the Aliberovskoye graphite deposit; in the Rep. Sakha (Yakutia) – near the Brindakit Settlement, in the massif Gornoye Ozero. In Transbaikalia, at the lazurite deposits of the region of Slyudyanka, sodalite in crystals up to 7x7 cm is called palagolite. In Tadzhikistan, in the upper reaches of the Zeravshan River the largest deposit of light blue sodalite is situated; also in Western Pamirs Mts. haüyne in larger masses similar to lazurite occurs in marble at Lyadzhvardara deposit.

In Europe, gem-quality blue sodalite was discovered in South Norway, at Tvedalen, Langesund, Telemark Dist., and also at the Sørøya Is., Finmark Dist. In this deposits are in Portugal – Serra de Monchique; in Romania – at Ditra ˘u, Harghita Dept., where ornamental sodalite rock with small white spots is called ditroite. In Great Britain, findings of sodalite are known in Scotland; in Italy – at the deposit Monte Somma, near Vesuvius. In Germany haüyne gem-quality in grains up to 1 cm. occurs at Mending, Effel Mts., and Rhineland-Palatiate. On Greenland, sodalite was extracted at the deposit Kangerdluarssuk, massif Ilimaussaq. In West Africa, in Namibia, transparent blue sodalite is extracted at the deposit Gopogo. In South Angola, aggregates of its crystals, up to 20 cm. wide, were found. In Myanmar (Burma), in the region of Mogok, at the Tajongnadin mine, perfect sodalite is extracted. In India, it was discovered in the Rajasthan State, near Kishingarh; in Afghanistan – in the Badahshan Prov., at the Sar-a-Sang deposit lazurite, where its colorless crystals reached 3 cm., also as hackmanite crystals up to 10 cm.

In Canada, in the Ontario Prov., at the deposit Princess Quarry, near Bancroft, they extract the best bright blue sodalite of gem-quality – Canadian blue stone. It has another name there, too – allomite, after C. Allome, who send it to trade. In the province British Columbia, in alkali massif Ice River there are rocks with significant part of blue sodalite. In the Québec Prov., at the deposit Mont St Hilair, they found crystals of dark blue sodalite, up to 2.5 cm., and violet one – up to 10 cm., and yellow one – up to 32.6 cm., as well as gem-quality hackmanit. A variety of dark blue sodalite from Canada has the trade name blue princess, because it was found in the period of the visit of the British King and his eldest daughter. Material good for faceting was called their royal sodalite. In Canada, sodalite is regard as a national symbol of country. Another source of ornamental sodalite for the world market is a large deposit in the Bahia State, Brazil. In Bolivia, it was extracted at the deposit Serro Sapo, Auopao Dept. Small deposits of ornamental light blue sodalite are in the U.S.A: Arkansas, at the deposit Magnet Cove, Hot Springs Co.; Montana – in pegmatites of the Berpo Mt.; Maine – at Dennis Hill, Kennebec Co., as bright blue masses up to 20x20 cm. Haüyne in Russia is known in lazurite rock at the deposit Slyudyanka, Irkutsk Region. In Tadzhikistan, it is found in lazurite rock at the deposit Lyadzhvardara, West Pamirs. In Germany, it was discovered in grained aggregates near Niedermendige, Rhineland-Palatinate. At the deposit Meien near Laacher Lake, Rhineland-Palatiate, haüyne in crystals of gem-quality, up to 2.5 cm. in size, exists in lava. In Italy, in the Alban Mts., at the Ariccia deposit, in carbonate xenoliths among leucite tuffs haüyne was taken for lazurite earlier. The same mistake was done in the U.S.A., in the New York State, at the deposit near Edwards, St Lawrence Co. Haüyne is also found at deposits of the states of Colorado, Montana and South Dakota; and in Canada – in the Québec Prov.

Synonyms. Sodalite – Allomite (alomite), after C. Allome, who send it to trade in Bancroft, Ontario, Canada | Glaucolite | Hackmanit, after Finnish petrologist V. Hackman (1866-1941) | Canadian jade | Lajwar, obs | Canadian lapis lazuli | German lapis lazuli | Noseanite (nosin, nosite) | Blue stone | Canadian blue stone.

Haüyne – Deodatite, after Fr. geologist Deodat G.S.T.G de Dolomi´u | Latialite, after the discovery location in Latium, Italy | Lazialite, obs. | Napolite | Spinelblende.

Nosean – Spinellan, obs.

Quality improvement. Under heating and X-rays irradiation light blue sodalite receives pink color, which is unstable in the sunlight. Hackmanit loses its color in the sunlight, but the color can be restored with X-rays irradiation. Under heating it becomes green at first, then – blue; and after cooling this color is kept.

Cut Gems. Solid blue aggregates of sodalite are good ornamental material for beads, cabochons and stone carving. Transparent stones can be faceted. Transparent light blue sodalite was used for adornments even in the time of Inca; we cold see it in the excavations in Bolivia, near Titikaka Lake. Gem-quality blue sodalite can be faceted; the biggest one was 15.33 ct. As a result of faceting of hackmanit for collection purposes a yellow stone with the weight 3.32 ct. was received. Ahuge sodalite ball was exhibited at the jewelry show in Tucson, the U.S.A., in 1997.

Haüyne is found as transparent crystals, from which faceted stones up to 3 ct. were made. Such stones from the deposit near Laacher Lake, up to 0.8 ct., with small brilliants the brooch “Butterfly” was decorated – it was sold for Swiss Fr. 45,000 at the auction in 1999. Ornamental haüyne is cut in cabochons.

Synthesis. Sodalite has been made artificially, since 1975, through replacement of chlorine to bromine, barium to lithium in its composition. Under heating with H2S it transfers to lazurite. With the same method synthetic lapis lazuli is also produced.

Similarity. Sodalite looks like azurite, haüyne, dumortierite, lazulite and lazurite. Haüyne is hardly differs from sodalite, it looks like lazurite and nosean.

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