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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

HEMIMORPHITE


HEMIMORPHITE (Hemimorphit—Hémimorphite—√емиморфит) (Kenngott, A. 1853), from Gk. “hemi” – half and “morphe” – from, because the lack of a center of symmetry or a mirror plane perpendicular to the c axis causes different terminations to appear at each end of the prism.

Composition & Properties. Silicate – Zn4[4][(OH)2|Si2O7]•H2O, subclass of diorthosilicates, rhombic system. Hardness 4.5-5. Density 3.5. Glass luster, silk to dull one. Perfect cleavage in two directions. Fragile. Pyro- and piezoelectric. Hemimorphite is found in the form of table or columnar crystals up to 6 cm. long, and also in massive bunch-like, stalactite or grained aggregates. Half-transparent to transparent. Color: white, colorless, rose, yellow, light blue – because of copper admixtures, green – because of iron (Fe2+), brownish – because Fe3+, black – because of manganese. Sometimes, it is stripped-colored.

Deposits. Hemimorphite is formed as a secondary mineral of the oxidation zone of ore veins. In Russia hemimorphite in crystals available for faceting was discovered in East Transbaikalia, at the Klichka, Taininskiy, Trekhsvyatitel’skiy and other mines in Nerchinsk area, as well as in the Primorskiy Region – at the Dal’negorskoye deposit. In South Kazakhstan, it was found at the deposits Suleyman Say and Ashchysay, Karatau Mts.; and in the Balkhash Region – in the form of colorless crusts of crystals up to 1.5 cm., also at the deposits Gul’shad and Kyzyl Espe; and in the Rudnyi Altai Mts. – at the Berezovskoye deposit. In North Tadzhikistan, crystals of hemimorphite at the deposits Darbaza and Takeli, Khujand Dist., in Karamazar Mts., were extracted. In Uzbekistan, collection material comes from the Kurgashinkan deposit in the region of Olmaliq (Almalyk). In Europe, hemimorphite is known in Belgium – at the Altenberg deposit (La Calamine), near Moresnet; in Romania – at the Dognecha deposit, Banat region. In Great Britain, at the Rowton Jill deposit, Cumbria, they found its massive aggregates of sky-blue hemimorphite and perfect green tones crystals. In the south of France, there is a deposit of massive light blue hemimorphite of ornamental quality in Serai, Haute-Pyrénées Mts. In Austria, it is found at the deposits Bleiberg and Reibl, Carinthia; in Italy – at the Monteponi deposit, Sardinia Is.; in Poland – at the Olkusz locality, Upper Silesia. In Algeria, hemimorphite is presented with well-formed crystals at the Djebel Guergour deposit, near Sétif. Its findings are also known in Namibia and Congo (Brazzaville) – at the Mfauti deposit; and in Zambia, at the Kabwe (form. Broken Hill) deposit. In Northern Vietnam, at the Tuj Diên deposit, near Bâc Can, and in Chò-Diên village. they extracted beautiful blue-light blue crystals of hemimorphite. In the U.S.A., perfect, half-transparent, solid masses of ornamental stripped-colored hemimorphite at the Sterling Hill deposit, New Jersey, they extracted; in Montana it was discovered in large crystals at the Elkhorn deposit; in Nevada – in green-light blue massive aggregates at the Eureka deposit; in Missouri crystals of hemimorphite were found at the Joplin deposit. In Mexico, colorless transparent crystals of hemimorphite up to 13 cm. long they discovered at the El Potosí mine and at Francisco Portillo, Santa Eulalia region, Chihuahua. They made faceted stones up to 2.5 ct. from them. In the region of Durango, they find its light blue crystals and solid masses at the Mahistral deposit.

Synonyms. Zincian prismatic baryte | Calamine, from Lat. “calamus” – rush, because of the similarity with its stalactite formations; the name was discredited by IMA | Azurra calamine | Electric calamine | Prismatic calamine | Galmei, obs. | Zincian luster | Glass zinc ore | Siliceous zinc ore | Smithsonite, mist. | Zinc spar.

Treatment. Massive blue aggregates are used for cabochons; transparent white crystals from Mexico were faceted for collection purposes – the gems were not more than 3 ct. In the Museum of Calgary, Canada, there is such a faceted hemimorphite in 1.9 ct.

Similarity. Hemimorphite looks like turquoise, prehnite, smithsonite and chrysocolla.

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