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Russian Gemstones Encyclopedia

Vladimir Bukanov. Russian Gemstones Encyclopedia

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HAMBERGITE


HAMBERGITE (Hambergit—Hambergite—√амбергит) (Brögger, W.C. 1890), after Axel Hamberg (1863-1933), a Swedish mineralogist and explorer, who attracted attention to the discovery of its specimen. Water borate – Be2[OH|BO3], orthorhombic system. Hardness 7.5. Density 2.4. Glass luster. Cleavage in two directions. Fragile. Hambergite is found in the form of columnar, often flattened crystals. Color: colorless, rose or pale yellow. Transparent to translucent. A rare mineral of alkali pegmatites.

Deposits. In Russia, its findings are known in Priladozhia, at the Pitkaranta deposit – crystals up to 3 cm.; in the Middle Urals, at the Mokrusha mine – crystals up to 5 cm.; in Central Transbaikalia, in oligoclase pegmatites of the Malkhan Ridge – transparent colorless crystals up to 6x1 cm. In 1987, in Tadzhikistan, at the East Pamirs Mts., gem-quality hambergite was discovered near Rangkul’ Lake, in pegmatites of the Mika deposit. In the same region, in the Turakuloma Ridge, in the upper reaches of the Kukurt River, in the vein “Fantasia” and in pegmatite of the Dorozhnyi deposit, they found rose and colorless crystals of hambergite up to 20 cm. long, with well developed tips. Besides, hambergite was found there as needle inclusions in crystals of quartz. In the West Pamirs Mts., to the southeast from Khorugh, in the Shakhdarinskiy Ridge, they found hambergite in the valley of the Tusion River.

Initially, hambergite was discovered in South Norway, near Barkevik and Helgeroa, in the region of Langesund, Telemark, where its crystals occur up to 3 cm., rarely 15x5 cm. In Czech Rep., its finding was made in pegmatite of the Enzlow II deposit, Moravia. As a gemstone, hambergite was valued after finding of its gem-quality varieties at several deposits of Madagascar. In the region of Antsirabe, at the deposits Anjanabonoina, Maharitra and in the Bity Mt., they found its crystals up to 11x4 cm. In India, in the Jammu and Kashmir State (disputed area), gem-quality hambergite crystals up to 7 cm. long were extracted at the deposits Dusso and Drot, in the region of Gilgit; as well as in pegmatite of Stack Nala, region of Shengusa. In the U.S.A., hambergite in crystals up to 6 cm. was discovered in California, at the deposits Little Three and Himalaya, near Mesa Grande, San Diego Co. Recent years, there is information about its findings in Brazil.

Treatment. Transparent crystals of hambergite are of collection interest because of their rarity. In the faceted form, they look like rock crystal, but display high level of double refraction. To show the intensity of color, they place the table facet of a stone perpendicular to its long axis. Stones more than 5 ct. are extremely rare, however in 1968 a faceted hambergite 28.86 ct. was sold.

Similarity. Hambergite looks like beryl, beryllonite, danburite, euclase, scapolite and zircon.

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