SERPENTINE, GROUP: ANTIGORITE, LIZARDITE, CHRYSOTILE
SERPENTINE group (Serpentin—Serpentine——ерпентин) (Dioscorides, P. 50 AD). The name is derived from Gk. “ophites”, of a serpent, because of the serpent-like mottled and scaly appearance of serpentine-bearing marbles. Serpentines are represented with three mineral kinds: antigorite, chrysotile and lizardite. Antigorite (Schweizer, E. 1840), after its discovery in the Val Antigorio, 35 km. NW of Lago Maggiore, Piedmont, Italy. Chrysotile (von Kobell, F. 1834), from Gk. “chrysos” – gold and “tilos” – fiber, alluding to its color and habit. Lizardite (Whittaker, E.J.W. & Zussman, J. 1956), after its discovery location in Kennack Cove, the Lizard, Cornwall, England.
Composition & Properties. General formula of this group of minerals: Mg6[(OH)8|Si4O10]. Antigorite and chrysotile are silicates, subclass sheet silicates, monoclinic system, and lizardite – trigonal and hexagonal system. Hardness 2-4. Density 2.2-2.6. Cleavage in one direction. Glass luster to greasy one: pearl one for antigorite, wax one for noble serpentine, or ophicite (ophite), silk one for chrysotile. Serpentine is a group name for minerals close in the content and structure. The widespread among them are: fibrous chrysotile, plated antigorite and lizardite. They are not described separately, because usually they are together in the content of the rock serpentinite – an ornamental stone, which is really widespread. Serpentines are represented with several varieties. Noble serpentine, or ophiolite (serpophite) is massive, translucent, with dull green color. It is usually composed with lizardite or antigorite. Common serpentine is non-transparent to half-translucent. Slickenside is typical for massive aggregates. Color: different tones of green, often spotty. Cerolite is represented with complete, almost amorphous masses. Chrysotile is found as fibrous, non-transparent aggregates, and chrysotile-asbestos – as parallel-fibrous aggregates; zermattit – as twisted-fibrous aggregates. A translucent variety of antigorite – picrolite not rarely displays the effect of cat’s-eye in cabochons, it has the trade names Californian cat’s-eye, picrolite cat’s-eye, serpentine cat’s-eye, schillerspar or satelite. The most brightly this effect is displayed in the replacement of fibers of chrysotile opal. Serpentinite, or zmeevik is massive rock, often colored nickel serpentine – alipite and with admixtures of nickel-containing clay minerals: garnierite, revdinskite and others. It is also characterized with multiple varieties. Color of serpentinite: white, yellowish, green of different tones, reddish, light bluish, sometimes lilac-blue. A stripped variety of gray to yellow-green zmeevik is called ricolite, and a fine-grained, translucent one – bowenite. Bright green noble serpentine is called williamsite. Porcelain-like, non-transparent greenish serpentinite is called porcellophite. Honey-yellow one with resinous luster is called retinolite. A massive dirty-green variety, composed with twisted-fibrous aggregates of antigorite is called nephritoid. Dark green to black serpentine is called nigrescite. Serpentinite not rarely contains mineral admixtures, which have an influence on its color. Admixture of magnetite forms spotty coloring in cerolite and mocha stone, opal presents in siliciophite and opal serpentine; brucite and magnesite – in marmolite. Frequent admixtures are also actinolite-tremolite, hematite and epidote. Serpentinite, intensely polluted with admixtures, is called neolith. A pseudomorph of opal on serpentinite is called opaline. There are typical inclusions of serpentine in faceted chrysolite and demantoid.
Deposits. It is formed under metasomatic transformation and in weathering crusts of hyperbasites, carbonate and magnesia rocks. As a result of serpentinization of marbles and intermediate to serpentinite, ornamental rock is formed – ophicalcite, colored green. If serpentinite is formed on magmatic rocks of the basic content, complete pseudomorphs on olivine and pyroxenes appear, keeping their shape. When pyroxene is replaced with serpentine, bronze-yellow with silk luster bastite is formed. With inclusions of goethite and hematite it displays the effect of cat’s-eye in cabochons – bastite cat’s-eye.
In Russia, on the Kola Penin., near Pechenga, they extract solid green serpentinite – Pechenga ophites and black serpentinites with pyrite and veins of green ophite as additional material. In the Northern Caucasus, in Karachaevo-Cherkessia, at the Shamen deposit of asbestos, they discovered yellow serpentinite, which is known under the local names – adygeite, karachaite or labite. There, in the Urupskiy Dist., near the railway station, there is the Bedenskoye deposit with serpentinite. In the Subpolar Urals Mts., in the upper reaches of the Vangyr River, they exploited the Vodorazdel’noye deposit with green and pale rose noble serpentinite. In the Middle Urals, there are significant deposits of bigspotty and spotty-stripped noble zmeevik. At the Mramorskoye deposit (also called Kosobrodskoye or Chusovskoye), on the bank of the Chusovaya River, the extraction of serpentinite has been hold since the 18th cent. And 15 km. north from this deposit the similar works are hold at the Shabry deposit. To the east from Yekaterinburg, at the Novo-Asbestovskoye deposit, they discovered amorphous serpentine – cerolite; at the Bazhenovskoye and Alapaevskoye deposits, they extract light yellow chrysotile serpentinite. In the South Urals, there is a significant quantity of deposits with ornamental serpentinite. In the Chelyabinsk Region, there are the Bakal’skoye and Ak Karginskoye deposits with yellowish serpentinite; and near Sungul’ Lake they found serpentine with admixture of sepiolite – sungulite. In the Uchaly Dist., Bashkortostan, there are the Iremel’skoye and Monitornoye deposits. In the Altai, they discovered rare pink-violet chromium-containing serpentinite. In the East Sayan, Mts., at the Gorlykgol’skoye deposit of nephrite such bedding rocks as serpentinites and ophicalcites are available as ornamental stones. On Kamchatka, they discovered the Kuyul’skiy massif of noble serpentinite. In Kazakhstan there is the Charskoye deposit of ophites in the Semipalatinsk Region, on the Char River; in the Jambul Region – the Anrakaiskoye deposit of serpentinites, and in North Kazakhstan, ornamental serpentinites are known at the Chugaevskoye and Kempirsai deposits. In the Karaganda Region, they find black serpentinite. In Azerbaijan, there is the Nagdaly deposit with small-spotty serpentinite; in Tadzhikistan – Biryuzakan deposit with veined-spotty salad-green serpentinite.
Because deposits of serpentinite are numerous and widespread, we will mention only those countries, where its varieties have their own names. In Ancient Greece, in Kasambale, near Thessaloniki, they extracted Thessalyan stone, or Thessalyan breccia – serpentinite with dendrite veins of calcite and fragments of breccia. In Italy, antigorite serpentinite, or antique serpentinite – verde antique marble was very popular. In the surroundings of Genoa and Sestri Levanto, in Liguria, in veins of white steatite, they found green to brown-red antigorite. In the south of Sweden, near Taberg, Jönköping, they described malachite-green antigorite serpentinite of fibrous structure – picrolite. In Finland, near Lappeenranta, they found stripped serpentinites with calcite veins – zebra stone; and near Kittilä they extracted noble serpentine. In England, on the Cornwall Penin., they discovered translucent greenish-yellow lizardite serpentinite, which was used as an ornamental stone; and in the west of Ireland, near Galway they extracted serpentinous Connemara marble, connemara, or Irish green marble. In Germany, lizardite serpentinite has been extracted near Zöblitz, Saxony, since the ancient times. In Poland, serpentinite was extracted at a deposit near Sobótka, WrocÍaw Region. In Romania, in skarns of the Ocna de Fier deposit, they discovered schweizerit, which was a mixture of antigorite, lizardite, chrysotile and sepiolite. In Switzerland, in the Swiss Alps, they discovered fibrous serpentine – schweizerit and twisted-fibrous one – zermattit.
In India, in the Jammu and Kashmir State (disputed area), translucent green bowenite is popular. In Punjab they made knives from it, because it possesses very high level of hardness – up to 4-5 on Mohs. We should mention especially half-transparent antigorite serpentinite from Pakistan, the market is full with carved produce from it. In Afghanistan, in the valley of the Kabul River, near Safed Kokh, they have known a deposit of dark green ornamental serpentinite since the deepest antiquity. In China, in the Hunan Prov., there is the Tuoyang deposit with yellowish-green noble serpentinite, which is called imperial’yu yen, or sang-i-yeshan. Souvenirs from it are offered to tourists under the names Hunan jade, new jade or Korea jade. In Mongolia there is the Boin Dalai deposit of serpentinite, earlier taken for nephrite. In New Zealand, translucent nephrite-like serpentinite, from which Maori made their axes, the local name was adapted – tangiwaite. On the South Is., there are its deposits, represented with translucent dark green and light bluish varieties. In Western Australia, similar serpentinite is called Pilbara jade after the Pilbara deposit.
In the U.S.A., they use many varieties of serpentinite. There is baltimorite – fibrous chrysotile from the Bear Hills deposit, Maryland; it is called antigorite sometimes. In Pennsylvania, nephrite-like serpentinite from the region of Chester is called williamsite.Another variety of green serpentinite from this state is taxoite and deweylite. Fine-sheeted, greenish-white and light bluish-green serpentinite from Hoboken, New Jersey, they call marmolite. Greenish-gray ornamental serpentinite from the Pelham deposit in Massachusetts they call pelhamine. In Delaware State and Rhode Island State, there are deposits of apple-green bowenite. In New Mexico ricolite is popular; it is bright green, stripped lizardite serpentinite from a deposit near Rico. In California, light bluish chrysotile serpentinite displays the effect of cat’s-eye after cut – serpentine cat’s-eye.
Synonyms. Serpentine and serpentinite – Adygeite, after the discovery location in the Adygeya, Northern Caucasus, Russia | Alipite, from Gk. “lipos” – fat | Baltimorite – chrysotile-asbestos, after the discovery location near Baltimor, Maryland, the U.S.A. | Bowenite, after the Amer. mineralogist G. Bowen, who described it, syn. Soochow jade | Dermatin, from Gk. “derma” – skin, obs. | Enophite – lizardite (?) | Californian tiger’s-eye, after the discovery location in the California State, the U.S.A. | Hydrophite | ~ jade: jasper ~, Kuen-Lun ~, serpentine ~, Soochow | Kitoit, after the Kitoy River, East Sayany Mts., Russia | Koreite, after the discovery location in Korea | Kupholit (kypholite), obs. | Marmolite, from Gk. “marmairo” – to glisten and “litos” – a stone, after the luster of the rock | Melopsite, from Gk. “melon” – an apple and “opson – pulp, after its color | Ophite, from Gk. “ophites” – resembling a snake, after the similarity of the color | Picrolite, from Gk. “picros” – bitter and “litos” – a stone, because of the content of Mg | Porcellophite | Retinalite, from Gk. “retine” – resin, after the color | Rocklandite | ~ serpentinite (zmeevik): noble ~, opal ~, Pakistan ~, precious ~, Vermont ~, Zeblitz ~. | Sinjak, Old Rus., after the blue color | Yu-en stone, Chinese, greenish-gray | Tangiwaite, from Maori “tangiwai” – tears, because its translucence, New Zealand | Vorhauserite | Williamsite, after the Amer. collector W. Williams | Imperial’yu yen, Chinese, greenish-gray | Zermattit, after the discovery location at the Zermatt deposit, Switzerland | Zmeevik, Old Rus.
Antigorite – Connarite, from Gk. “connaros” – ever-green wood, green nickel-containing | Karpinskite, after the Russ. geologist A.P. Karpinskiy (1847-1936).
Chrysotile – Asbophite | Italian asbestos | Snake asbestos | Woody asbestos.
Lizardite – schillerspar.
Quality improvement. Pale colored and colorless differences of noble serpentinite with low content of iron (Fe3+) can be transferred into rose tone using of gamma-rays.
Treatment. Serpentinite was known as an ornamental stone even in the period of ancient civilizations in the 3d millennium B.C. It was one of the first materials for carving of cylindrical stamps. In the countries of the East it is still popular for imitation of more expensive and difficult in cut stones – nephrite and jadeite. In pre-Columbian America, they carved amulets and ritual objects from serpentinite. In Europe, noble serpentinite was used at first in Saxony, more than 400 years ago. There were its deposits near Zöblitz. At first, they made drug vessels from it, that’s why it is called pharmaceutical stone. Later, they carved more exquisite things from it. In the Grün. Gew., Dresden, Germany, they expose a vase from serpentinite, 15.5 cm. high, made by German masters in 1500. In the Museum Hist. Nat., Paris, France, they keep a cup from serpentinite, made in Germany in 1628. In Poland, they made a wonderful pulpit from serpentinite in the church of St Magdalena in WrocÌaw. In the Pavlovsk Palace by St Petersburg there is a table adornment from this stone. Because of its low hardness and diversity of colors, serpentinite was widely used in the Florentine mosaic. It is often represented in the works by masters of the firm of K. Fabergé. In the Easter Egg “Colonnade” (1905) columns were made from serpentinite, and the egg-clock in the style of Louis XVI was established on them. High ornamental properties of the stone and significant quantities of deposit let the possibility to use it for manufacturing of tables, fire-places coating and decorations of palace interiors. Nowadays, it is used in coating of subway stations and the Palace of Congresses in the Moscow Kremlin. Till now, Ural and Tyva stone-carvers make vases, caskets, desk set, candlesticks, frames, Easter Eggs and other souvenirs from serpentinite.
Legends. In Ancient Rome, they considered, that this mineral helped at stings of snakes. As an amulet, serpentinite protects against snakes bites, according the principle of similarity. Astrologers believe it is a dangerous stone. According the Bible legend, Adam has bitten off a piece of the apple received from the snake the tempter, choked with this piece and split it out. The piece has turned into serpent stone. This stone is a lucky one for those, who were born under the signs of Capricorn and Virgo. In Ireland, noble serpentinite (connemara). In the U.S.A., serpentinite serves as an official emblem of California, and bowenite – as an emblem of Rhode Island.
Similar Gemstones & Imitations. Serpentinite in carved produce is often taken for nephrite, marble onyx and some jades (See App. 17). As a substitute of serpentinite, pseudophit can be met, it is composed with fine-flaked chlorite, and which is called Styrian jade in Austria. Green with red and yellow spots verdite, or Transvaal jade from South Africa resembles it; this material is composed with Cr-mica fuchsite. Widespread analogues of serpentinite are pertly serpentinous greenstone rocks: ophicalcite, green antique porphyry and some varieties of green gabbro.