gems, Somalia, Somaliland, ruby, sapphire, garnet

Recent geological surveys indicate that Somaliland has abundant deposits of gemstones, from emerald to aquamarine, ruby and sapphire as well as vast amounts of garnet, quartz and opal, and lesser-known minerals such as titanite and vesuvianite. Somaliland in northern Africa appears to be the new potential gemstone-bearing area comparable to Madagascar or Tanzania. In addition to pegmatite, which are the host rocks of emerald and other kinds of beryl such as aquamarine, Somaliland has metamorphic rocks that hold nodules of ruby and sapphire. There is little understanding of its mineral deposits, but villagers in Somaliland use primitive tools to dig out a range of gemstones that they offer for sale to dealers locally. When aid officials at the European Community (EC) office in the capital, Hargeisa, first saw the gemstones, they believed they had been stolen from graves. To determine whether these stones came out of the ground or were stolen, EC invited Dr. Judith Kinnaird, a consultant geologist and gemmologist from the University of Witwatersrand in Johannesburg, to investigate. Dr. Kinnaird visited the country twice and, in addition to identifying gem minerals, she helps local miners distinguish among similar coloured minerals and is working with Progressive Interventions (supported by EC funding) to help set up a gemmological association and marketing channels. Somaliland is part of the Mozambique Belt and was formerly part of the same landmass as Madagascar, Tanzania, Sri Lanka and India prior to continental drift. Recovery of gemstones began only in 1988 and is still carried out in a primitive and haphazard manner. The gem-producing belt is a narrow strip between 30 and 80 km wide and 200 to 300 km long, running roughly parallel to the Gulf of Aden. The country, once a British protectorate, suffered a nine-year civil war from 1982, leaving infrastructure like roads and bridges in disrepair. Dr. Kinnaird described access to gem deposits as difficult and hazardous. The terrain includes high mountains and coastal regions with temperatures reaching up to 50°C. Two emerald-producing areas, Alihiley and Simodi, occur at the contact of pegmatite and chromium-bearing schist. Patchy colour development and dual-colour zoning were observed in crystals. At Simodi, pegmatite is visible across the hillsides, and emerald is being mined again after years of inactivity, despite dangerous pit conditions and lack of equipment. In Alihiley, rudimentary mechanical tools like a compressor are used. East of the emerald belt, aquamarine and other beryls occur in pegmatite intruding granite, giving rise to large but often cracked crystals coloured by iron or titanium. Reports also mention yellow beryl (heliodor). Ruby and sapphire are found in metamorphic rocks, not pegmatite. Ruby has been found in red corundum cores with green zoisite, while sapphire occurs in nodules, greenish-blue near the surface and better-quality blue material at depth. Unlike other African countries, ruby and sapphire are not found together. Garnet is extremely abundant, in red to orange colours and of multiple types, including pyrope and almandine, and some green garnets initially mistaken for Tsavorite were identified as vesuvianite. Orange to yellow opals lacking play-of-colour have been found, but high-quality reddish opal with good play-of-colour also occurs, possibly in both lava and gypsum/anhydrite strata. Quartz is widespread, including high-purity rock crystal, smoky quartz, banded forms, and deep purple amethyst. Additional minerals include red spinel, watermelon tourmaline, colourless topaz, blue and green vesuvianite, titanite, apatite, and zircon. Some locals mistake quartz for diamond, though Dr. Kinnaird clarified there are no diamonds in Somaliland.

gems, pegmatites, Urals, Russia, beryl, topaz, tourmaline, feldspar, emerald, alexandrite, phenakite intergrowth

The northern section of the central Ural Mountains of Russia includes notable miarolitic pegmatites carrying beryl, topaz and tourmaline in the western endo and exocontact of the Mursinka-Adui intrusions and the desilicated pegmatites surrounded by emerald-alexandrite-phenakite mineralization. Fine blue topaz with smoky quartz and albite is found at the Mokrusha, Golodnij, Tyazhitnitza, Staraja Mylnitsa, Starzewa Jama and Kazionnitsa mines. Gem-bearing pegmatites NW of Mursinka are enclosed in a serpentine and contain miaroles with coloured tourmaline: pegmatites to the W and SW contain green and yellow beryl and yellow or light blue topaz. The Sarapulka and Shaitanka pegmatites are thin veins with rubellite and rhodizite in the W and green and blue aquamarine in the E. Large amounts of emerald, alexandrite and phenakite have been produced since 1830 from the Takovaja district schists. Specimens recently discovered include combinations of phenakite/emerald and alexandrite/emerald. The southern Ural region centred on Miass in the Ilmen Mountains produced clear topaz crystals up to 3-4 kg and uncommon green beryl associated in miarolitic pegmatites with amazonite.

corundum, sources.12, Tanzania.12, gems

Tanzania emerged as a great producer of colored gemstones in the second half of this century. Most of the important localities (e.g., Longido, Lake Manyara, Merelani, and Umba) are in the northern part of the country; they produce a great variety of gems, the most impor-tant being tanzanite, corundum (ruby and fancy-color sapphires), garnet (particularly rhodolite and tsavorite), tourmaline, emerald, alexandrite, spinel, and quartz. Diamonds are mined from the Mwadui kimberlite pipe, also in the north. Historically, gemstone occurrences in the south have been rare.. In 1994, however, large and rich gem deposits were found in southern Tanzania in the vicinity of Tunduru, about 80 km north of the border with Mozambique. An estimated 80,000 “illegals” have been working the alluvial deposits in the vicinity of the Muhuwesi and Mtetesi Rivers, mostly by primitive methods. Although the primary sources of the gem minerals have not been found, the fact that some crystals are only slightly rounded indicates short transport distances. This article discusses the history of the discovery and the development of gemstone trade in this area, the geologic setting of the deposits (in the Proterozoic Ubendian-Usagaran System of metamorphic rocks), and the most important gem materials found to date. These include blue and fancy-color sapphires, ruby, many colors of spinel, garnet (rhodolite, hessonite, and color-change), and chrysoberyl (cat’s-eye and alexandrite).PB

gems, beryl, emerald, Colombia, politics, drug war

Details Colombia’s drug wars, which have also involved some members of the emerald trade.

gems, glyptic, engraved gems, agate, cameo, intaglio, England, chalcedony, chrome chalcedony

beryl, emerald, Mozambique, gems

gems, inclusions, beryl, emerald, Madagascar

corundum, history, India.12, gems, Indian lapidary

Silva examines the trade in precious stones in sixteenth-century Lisbon, when Portuguese maritime expansion made the city a major European entrepôt for gems arriving from India and other parts of Asia. Drawing on contemporary documentary sources, he discusses the importation, valuation and sale of diamonds, rubies, sapphires, emeralds, pearls and other precious materials, together with the merchants, jewelers and lapidaries involved in their distribution. The influx of eastern gems attracted foreign lapidaries to Lisbon and contributed to the development of a specialized gem and jewelry trade. The study also considers commercial practices, including the packaging and valuation of shipments and the role of foreign banking and mercantile houses, placing the gemstone trade within the broader economic consequences of Portuguese expansion in the Indian Ocean. Later work by Silva developed the subject in English as “The Portuguese Gem Trade in the Sixteenth Century” (Jewellery Studies, No. 6, 1993, pp. 19–28).

gems, beryl, emerald, inclusions, Brazil

synthetic beryl, emerald, gems