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It was mined since the 12th century in Saxony, in the silver mines located there. [17] Heating can be used to distinguish azurite from purified natural ultramarine blue, a more expensive but more stable blue pigment, as described by Cennino D'Andrea Cennini. Ultramarine withstands heat, whereas azurite converts to black copper oxide. [18]
In early 2011, the town received a grant of just over $10,000 from the Arkansas Rural Community Grant Program. The grant requires that the amount be matched locally. Volunteer hours can contribute to the match. One of the plans for the money is to refurbish the historic Missouri and North Arkansas Railroad depot in St. Joe. [6] [needs update]
Azurite has a dark, rich blue color - its formula, Cu3(CO3)2(OH)2, is very close to malachite. The blue color of azurite is from Cu+, while the green color of malachite is from Cu+2. Azurite & malachite almost invariably occur together, and are telling indicators of copper in the field, even in very small quantities.
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Located within Central Arkansas, the city is named for bauxite, the source ore for aluminum, which was found in abundant quantities in the area and became a source of aluminium refining. The city's population boomed during expanded aluminium production during World War II and shrank rapidly with output of the ore.
Initially, Arkansas bauxite met 90% of US aluminum demand. Underground mining before and during World War II gave way to open pit mining in the 1960s. During the war, up to six million tons were mined in 1943. Arkansas bauxite mines were often passed over in favor of higher quality bauxite reserves in the Caribbean and mining ceased in 1982.
Huntington is a city in Sebastian County, Arkansas, United States. It is part of the Fort Smith, Arkansas - Oklahoma Metropolitan Statistical Area . As of the 2010 Census the population was 635.
Pages in category "Mining in Arkansas" The following 14 pages are in this category, out of 14 total. ... 1915–1917 Wheelbarrow Mine strike; B. Batesville mine; C ...