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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

PALYGORSKITE, GROUP: PALYGORSKITE, SEPIOLITE


PALYGORSKITE group (Palygorskit—Palygorskite—ѕалыгорскит) (Savchenkov, T. 1862), after its discovery location in Russia at the Palygorsk Division mine, near the Popovka River, Perm’ Region. Here we also describe sepiolite, which forms a row of constant miscibility with palygorskite.

Composition & Properties. Silicate – (Mg,Al)4[OH|(Si,Al)4O10]•(4+4)H2O, subclass sheet silicates, monoclinic system. Hardness 2.5-3. Density 2.1-2.3. Wax luster. Fragile. Palygorskite is found in the form of fine-fibrous aggregates, forming felt-like and cryptocrystalline masses. Because of the similarity with skin, these aggregates are called mountain skin, and rose ones – angel skin. Sometimes, they look like timber – mountain wood, or mountains cork. Palygorskite is often found in weathering crusts of serpentinites and magnesio-carbonate rocks. It forms lenses and pockets, fills cracks. Color: white, gray, yellowish, brownish. Usually, it contains admixtures of quartz, calcite, pyrite and plagioclase. Massive accumulations of rose palygorskite look like opal or coral. They are used as an ornamental stone in small stone carving and in cabochons. In Russia, palygorskite was discovered in significant accumulations in the Moscow and Volga Regions, not far from Arzamas – by the village of Velikiy Vrag; and also near Nizhniy Novgorod – by Gorbatov on the Oka River and in some other places. Palygorskite of jewelry-ornamental quality is known in Slovakia – at the Lovinabanja deposit, as well as in Mexico and Peru.

Synonyms. Attapulgite, after the discovery location near Attapulges in the Georgia State, the U.S.A. | Bergwolle, Germ. | Mountain cork | Lassalite (lassallite), after surname M. Lassal | Mountain meat | Angel’s skin opal | Mountain paper | Pilolite, ferriferous | Mountain silk | Devils skin | Mountain skin | Mountain wood | Mountain wool.

Sepiolite (Sepiolit—Sépiolite——епиолит) (Glocker, E.F. 1847), from Gk. “sepion” – cuttle-fish bone, because of its low density and porous, bone-like appearance. Silicate – Mg8[(OH)2|Si6O15]2·(4+8)H2O, orthorhombic system. Hardness 2-2.5. Density 2-2.3. Dull luster. Fragile. It forms an isomorphic row with palygorskite. An alteration product of serpentinite and magnesite in serpentinites. It is found in the form of solid nodules of white, rose, reddish or greenish-blue color or as non-transparent accumulations, which cement other minerals. The size of nodules is up to 20 cm. in cross-section. In Russia, it is found in small volume in the Murmansk Region, at the Kovdor deposit. In the Lovozero massif on the Kola Penin. they discovered manganese sepiolite. In the Middle Urals, at the Bazhenovskoye deposit, and in the South Urals, at the Akkermanovskoye deposit, nickel sepiolite is found in the form of solid yellowish-white and greenish-blue masses. In the north of the Krasnoyarsk Region, at the Kugda deposit, solid masses of sepiolite fill cavities in chrysolite veins. It was found also at the Talnakh copper-nickel deposit, near Noril’sk. The best ornamental sepiolite is extracted in Turkey, to the southwest from Ankara, in the region of Eski¸ sehir and Yunak, Konya vilayet. It is represented there with massive layers in lime-stones, which were discovered even in the antique times and has been actively exploited in the 15th cent. and later. Besides, findings of sepiolite or meerschaum are known in Spain, at Vallecas, near Madrid; in Czech Rep. – in serpentinites at Biskoupky, near Grubshice in Moravia; in Greece – on the Samos Is. In Kenya, a sepiolite deposit was discovered in the region of Amboseli Lake; in Tanzania, its deposit is situated in the Masai Dist.; in Morocco, sepiolite is known as Morocco soapstone. In Japan, on East Hokkaidö, in the Ankan area, ferrisepiolite, or xylotilite is represented with a dyke, up to 1.5 m. thick. In Greenland, in the alkali massif Ilímaussaq, they discovered manganese sepiolite. In the U.S.A., ornamental sepiolite was extracted at one of the deposits on the Jila River in New Mexico, as well as in Pennsylvania, as nodules up to 10 cm. in Delaware Co. and Chester Co.

Synonyms. Aphrodite | Canary ivory | Quincite (quinzite), Amer., after the discovery location near Quincy, Illinois, the U.S.A. | Ferrous sepiolite. | Xylotilite, from Gk. “xylon” – wood.

Sepiolite is used in stone-carving under the trade name meerschaum. They manufacture pipes and cigarette holders from it, as well as some other produce; then, they saturate these things with oils, which give them strong luster.

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