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Thursday, July 23, 2009

Wisconsin "Ruby" ??

Even though several gemology and other semi-official sites list the Ruby as Wisconsin's State gemstone, nothing can be found officially where the State Legislature ever declared it as the State gem.
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What is listed in Official Wisconsin documentation is that Galena (Lead sulphide) a combination of abundance, uniqueness, economic value, historical significance and native nature, lead to the appointment of Galena as the State mineral in 1971. Galena is the primary ore mineral of Lead. Worked for its lead content as early as 3000BC, it is found in ore veins with Sphalerite, Pyrite and/or Chalcopyrite, and in Sedimentary rocks as beds or impregmentations. The crystals are bright when fresh but often receive a dull tarnish after exposure to air.
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Likewise Red Granite was chosen for its economic importance in the state in 1971 as the State rock. This speckled rock is composed of quartz and feldspar. Granite is an igneous rock and is formed from magma. Granitic magma has many potential origins but it must intrude other rocks. Most granite intrusions are emplaced at depth within the crust, usually greater than 1.5 kilometres and up to 50 km depth within thick continental crust. The origin of granite is contentious and has led to varied schemes of classification. Classification schemes are regional; there is a French scheme, a British scheme and an American scheme. This confusion arises because the classification schemes define granite by different means. Generally the 'alphabet-soup' classification is used because it classifies based on genesis or origin of the magma.
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