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Cobalt | |
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State | Ontario |
Country | Canada |
Capital | |
Population | 1128 |
Cobalt is a chemical element with the symbol Co and atomic number 27. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal.
Cobalt-based blue pigments (cobalt blue) have been used since ancient times for jewelry and paints, and to impart a distinctive blue tint to glass, but the color was later thought to be due to the known metal bismuth. Miners had long used the name kobold ore (German for goblin ore) for some of the blue-pigment-producing minerals; they were so named because they were poor in known metals, and gave poisonous arsenic-containing fumes when smelted. In 1735, such ores were found to be reducible to a new metal (the first discovered since ancient times), and this was ultimately named for the kobold.
Today, some cobalt is produced specifically from one of a number of metallic-lustered ores, such as cobaltite (CoAsS). The element is, however, more usually produced as a by-product of copper and nickel mining.
Tbilisi | |
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State | |
Country | |
Capital | |
Population | 1132000 |
Tbilisi (English: tə-bih-LEE-see, tə-BIL-ih-see; Georgian: თბილისი [tʰbilisi] (listen)), in some countries also still known by its pre-1936 international designation, Tiflis ( TIF-lis), is the capital and the largest city of Georgia, lying on the banks of the Kura River with a population of approximately 1.5 million people. Tbilisi was founded in the 5th century AD by Vakhtang I of Iberia, and since then has served as the capital of various Georgian kingdoms and republics. Between 1801 and 1917, then part of the Russian Empire, Tbilisi was the seat of the Imperial Viceroy, governing both Southern and Northern Caucasus.
Because of its location on the crossroads between Europe and Asia, and its proximity to the lucrative Silk Road, throughout history Tbilisi was a point of contention among various global powers.
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