Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia



CHLORITES, group (Chlorite—Chlorites—’лориты) (Werner, A.G. 1789), a group name from Gk. “chloros” – green, alluding to its color. Chlorites – silicates, subclass sheet silicates. Monoclinic system. Hardness 2-2.5. Density 2.5-3.3. Cleavage in one direction. The typical representative of this group is clinochlore. To varieties chlorites concerns are ripidolite, kämmererite and kochubeite.

Clinochlore (Klinochlor—Clinochlore— линохлор) (Blake, W.P. 1851), from Gk. “klinein” – to incline and “chloros” – green, after its color and the great obliquity between its optic axes. Composition – (Mg,Fe2+,Al)3[(OH)2|AlSi3O10] (Mg,Fe2+,Al)3(OH)6, subclass sheet silicates, triclinic system. Hardness 2. Density 2.6-2.7. Glass luster to pearl one on cleavage. Cleavage in one direction. Non-transparent to translucent on the edges. Color: grass-green, olive-green to greenish-gray. Clinochlore is represented with plate crystals, large-foliated aggregates of the radial-rayed structure, sphaerolites and solid flaked masses The size of giant sphaerolites reaches 0.5 m. in diameter. An ornamental stone of massive clinochlore has he trade name seraphinite. When processed, it displays pearls luster because of zone and radial-rayed structure of its aggregates. Clinochlore and others chlorites are wide-spread. Usually, they are represented with solid fine-flaked masses, and also they are found as inclusions in gemstones in the shape of plates and worm-like aggregates. In rock crystal, chlorite flakes are observed as “powder” on the zones of growing, because of which so called “phantoms” are formed. In crystals of landscape quartz, chlorites with sericite and with other minerals form decorative groups of inclusions. Patterns of moss agate also can be connected with chlorite inclusions. Chlorites are represented also in non-transparent green varieties of chalcedony – heliotrope, plasma and prase. Chlorite is found at deposits of different genesis; it is a rock-forming mineral. As solid masses of pseudophite or chlorite schist, it is classified as one of ornamental jades – Styrian jade, and serpentinite with clinochlore – Pilbara jade. As an ornamental variety, basaltic glass – palagonit (See obsidian) also can be classified; it consists mainly of chlorite. As solid masses, also a violet-pink variety of chrome-clinochlore is found – kämmererit, with the content of Cr2O3 up to 4%, or kochubeite with the content of Cr2O3 more than 4%. Massive varieties of chlorites of the jades type are classified as non-expensive ornamental stones; they are processed in cabochon, but usually they are used for stone-carving as imitation of nephrite or jadeite.

Deposits. Chlorites are formed in magmatic and metamorphic rocks, in contact metasomatic, hydrothermal veins and in sedimentary rocks. Clinochlore is found as a product of metamorphism of magnesia rocks. In Russia, in the Polar Urals, clinochlore was discovered as crystals, 7x5 cm. in size, in the Geograph Mt., in the upper reaches of the Levyy Kachpel’ River. At the Middle Urals, it was discovered in the Zhuzhiny Mts., at the Bilimbaevskiy mine. Kochubeite is found at the Urals as complete massive and as veins along cracks in chromites at the Itkulskoye, Sarany, Biserskoye and other deposits. In the Subpolar and Middle Urals, in alpine veins, they find crystals of rock crystal with ornamental inclusions of chlorite – ripidolite. Similar jewelry-ornamental material is found in alpine veins in other countries, too. In the South Urals, in the Shishimskie Mts. clinochlore in well-shaped crystals is found at the Nikolaevsko-Maximilianovskaya mine, in the Zlatoust Dist. In the Irkutsk Region, at the Korshunovskoye deposit near Zheleznogorsk-Ilimskiy they extract an ornamental variety of clinochlore – seraphinite. In Poland, they discovered at Strzegom deposit as manganese-containing massive variety of chlorite – strigovite. In Austria, at the Zillertal deposit in Tyrol, crystals of clinochlore were found in alpine veins; and at the Gurtipol deposit they found beautiful aggregates of gray-green clinochlore – miskeyite. In Australia, in New South Wales ornamental pseudophite is extracted in serpentinites of the Hanging Rock Dist. In West Australia, at the Pilbara deposit, in the region of Marble Bar, they extract serpentinite with inclusion of relict chromite, replaced with clinochlore, under the trade name of Marble bar jade. Its color is dark green with light stripes and grayish-white spots of chrysotile. It is available for polishing and is classified as a non-expensive ornamental stone. Among the other countries, findings of clinochlore are known in the U.S.A., at the deposits Tilly Foster and Brewster, New York State; and in the Pennsylvania State, at the deposits Chester and Woods mine, where its crystals reach 18 cm. in cross-section.

In Russia, findings of kämmererit are known in the Middle Urals, at the Sarany deposit; and also at the Gologorskaya mine near Pervoural’sk; and in the Zhuzhiny Mts., near the Bilimai Settlement, in the South Urals, kämmererit was discovered near the railway station of Kartaly at the Verblyuzhka deposit, where its crystals reached 6 cm. in cross-section. In other countries, kämmererit is known in East Turkey, at the deposits Pembegul and Kop Krom, near Aškale, Erzurum vilayet. In the region of Erzurum, transparent crystals of kämmererit, up to 3 cm. in cross-section, are available for making faceted stones with the alexandrite effect. In the U.S.A., kämmererit is complete masses, available for cut in cabochon, it extracted at chromite mines of Pennsylvania.

Synonyms. Chlorite – Aphrosiderite | Styrian jade, after the discovery location in Styria, Austria | Pseudophite, from Gk. “pseudos” – false because of its similarity with ophite | Strigovite, after the discovery location near Strigau (now Strzegom), Lower Silesia, Poland.

Clinochlore – Allophite | Angaralite, after its discovery locality, by Angara River, Eastern Siberia, Russia | Serpentine chlorite | Chrome-chlorite | Pilbara jade, after the discovery location by Pilbara, West Australia | Prasolite | Leuchtenbergit, after the surname duke M. Leuchtenberg | Mauléonite, after the discovery location by Mauléon, France | Rhombohedral talc mica | Miskeyite, after the Austrian geologist J. Miskey | Rhodophyllite, from Gk. “rodon” – a rose and “phillon” – a leaf, after its color and cleavage | Sheridanite, after the discovery location by Sheridan, the U.S.A.

Kämmererit, after the main Russian mining druggist A.B. Kemmerer (1789-1885), who first noticed this mineral | Kochubeite, after the Russ. collector of minerals, honored member of the Russian Mineralogical society P.A. Kochubei (1825-1892) | Rhodochrom, from Gk. “rodon” – a rose and chemical element Cr, after its color and content.