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Umba Sapphires
The Umba sapphire is a unique type of sapphire discovered in 1962 in the Gerevi Hills, north of the Umba River in the Umba Valley of Tanzania. Umba sapphires exhibit coloration not common to sapphires found in other parts of the world, and are recovered from the alluvial deposits of the Umba River. , the Tanzanian government prohibits export An export in international trade is a good produced in one country that is sold into another country or a service provided in one country for a national or resident of another country. The seller of such goods or the service provider is an ... of these sapphires. References African Journals Online listing Corundum gemstones ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sapphire
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide () with trace amounts of elements such as iron, titanium, chromium, vanadium, or magnesium. The name sapphire is derived via the Latin "sapphirus" from the Greek "sappheiros", which referred to Lapis lazuli, lapis lazuli. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors. Red corundum stones also occur, but are called ruby, rubies rather than sapphires. Pink-colored corundum may be classified either as ruby or sapphire depending on locale. Commonly, natural sapphires are cut and polished into gemstones and worn in jewellery, jewelry. They also may be created synthetically in laboratories for industrial or decorative purposes in large boule (crystal), crystal boules. Because of the remarkable hardness of sapphires 9 on the Mohs scale of mineral hardness, Mohs scale (the third hardest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umba River (Tanzania)
The Umba River is located in northeastern Tanzania in Tanga Region. It rises in Schageiuforest (Shagayu) in the West Usambara Mountains at 2,000 m altitude and flows on the north side of the mountain range to the east. At Lelwa it empties the Mbalamu River, which comes from the extreme north of the Usambara Mountains, and the Mglumi River into the Umba. Just before the Umba flows into the Indian Ocean, it crosses the border to Kenya. The mouth itself marks the most eastern point on the border between Tanzania and Kenya, which was largely made in a straight line to the northwest towards Lake Victoria in the 19th Century. On the upper reaches of the river in the mid-1960s rich deposits of precious stones, including sapphires and spessartine, were discovered. Also on the river is the Umba River Game Reserve, a wildlife reserve that includes along with the Mkomazi Game Reserve, about 2,600 km². Hydrometry The flow of the river has been observed over 40 years (1963-2003) in M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umba Valley
Umba Valley is a geographic area in Tanzania and the world's only source of Umba sapphires. The Umba River flows through the Umba Valley. Specifically, Umba Valley is located in the north of the Usambara Mountains in the Tanga Region of Tanzania. See also * Geography of Tanzania Tanzania comprises many lakes, national parks, and Africa's highest point, Mount Kilimanjaro (). Northeast Tanzania is mountainous, while the central area is part of a large plateau covered in grasslands. The country also contains the souther ... References Mindat listing Valleys of Tanzania {{Tanzania-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanzania
Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and the Indian Ocean to the east; Mozambique and Malawi to the south; Zambia to the southwest; and Rwanda, Burundi, and the Democratic Republic of the Congo to the west. Mount Kilimanjaro, Africa's highest mountain, is in northeastern Tanzania. According to the United Nations, Tanzania has a population of million, making it the most populous country located entirely south of the equator. Many important hominid fossils have been found in Tanzania, such as 6-million-year-old Pliocene hominid fossils. The genus Australopithecus ranged across Africa between 4 and 2 million years ago, and the oldest remains of the genus ''Homo'' are found near Lake Olduvai. Following the rise of '' Homo erectus'' 1.8 million years ago, humanity spread ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Export
An export in international trade is a good produced in one country that is sold into another country or a service provided in one country for a national or resident of another country. The seller of such goods or the service provider is an ''exporter''; the foreign buyer is an '' importer''. Services that figure in international trade include financial, accounting and other professional services, tourism, education as well as intellectual property rights. Exportation of goods often requires the involvement of customs authorities. Firms Many manufacturing firms begin their global expansion as exporters and only later switch to another mode for serving a foreign market. Barriers There are four main types of export barriers: motivational, informational, operational/resource-based, and knowledge. Trade barriers are laws, regulations, policy, or practices that protect domestically made products from foreign competition. While restrictive business practices sometimes hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corundum Gemstones
Corundum is a crystalline form of aluminium oxide () typically containing traces of iron, titanium, vanadium and chromium. It is a rock-forming mineral. It is a naturally transparent material, but can have different colors depending on the presence of transition metal impurities in its crystalline structure. Corundum has two primary gem varieties: ruby and sapphire. Rubies are red due to the presence of chromium, and sapphires exhibit a range of colors depending on what transition metal is present. A rare type of sapphire, padparadscha sapphire, is pink-orange. The name "corundum" is derived from the Tamil- Dravidian word ''kurundam'' (ruby-sapphire) (appearing in Sanskrit as ''kuruvinda''). Because of corundum's hardness (pure corundum is defined to have 9.0 on the Mohs scale), it can scratch almost all other minerals. It is commonly used as an abrasive on sandpaper and on large tools used in machining metals, plastics, and wood. Emery, a variety of corundum with no value as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining In Tanzania
Tanzania is a land rich in minerals. Mining makes up more than 50% of the country's total exports, of which a large part comes from gold. The country has gold reserves of 10 million ounces, generating revenue of over a billion USD. Diamonds are also found in significant amounts. Since it was opened in 1940, the Williamson diamond mine has produced 19 million carats (3,800 kg) of diamonds. Gemstones, nickel, copper, uranium, kaolin, titanium, cobalt and platinum are also mined in Tanzania. Illegal mining and corruption are ongoing problems. In 2017, the government passed a series of bills aimed at increasing revenue from minerals after a scandal which caused the dismissal of the Minister for Energy and Minerals. History Although the mining industry was originally government owned and controlled, the mining laws were relaxed in the 1980s and 1990s to allow for private ownership of mining claims and the introduction of foreign companies. In 2008, the mining industry employed an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
