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An amethyst geode that formed when large crystals grew in open spaces inside the rock. The largest amethyst geode found as of 2007 was the Empress of Uruguay, found in Artigas, Uruguay in 2007. It stands at a height of 3.27 meters, lies open along its length, and weighs 2.5 tons. Amethyst is also found and mined in South Korea. [19]
A geode (/ ˈ dʒ iː. oʊ d /; from Ancient Greek γεώδης (geṓdēs) ' earthlike ') is a geological secondary formation within sedimentary and volcanic rocks. Geodes are hollow, vaguely spherical rocks, in which masses of mineral matter (which may include crystals) are secluded.
Amethyst is a form of quartz that ranges from a bright vivid violet to a dark or dull lavender shade. The world's largest deposits of amethysts can be found in Brazil, Mexico, Uruguay, Russia, France, Namibia, and Morocco. Amethyst derives its color from traces of iron in its structure. [37]
The Empress of Uruguay is the world's largest amethyst geode, standing at a height of 3.27 meters. It is open along its length and weighs 2.5 tons in its current state. It was discovered in 2007 in the Artigas department, Uruguay by the Uruguayan mining company Le Stage Minerals.
Cattierite (Co S 2), vaesite (Ni S 2) and hauerite (Mn S 2), as well as sperrylite (Pt As 2) are similar in their structure and belong also to the pyrite group. Bravoite is a nickel-cobalt bearing variety of pyrite, with > 50% substitution of Ni 2+ for Fe 2+ within pyrite.
[6]: 18 When the silica concentration of the gel is too low, a hollow center forms, called an agate geode. [10] [6]: 17 Quartz forms crystals around the cavity, with the apex of each crystal pointing towards the center. Occasionally, the quartz may be colored, such as amethyst or smoky quartz. Level-banded agates form when chalcedony ...
The presence of neurofibrillary tangles in the brain is one of the key hallmarks of Alzheimer’s disease. These irregular clumps of protein are closely associated with disease progression.
There are two ways to do this, which can be thought of as two notations which represent the same structure. In the usual so-called obverse setting, the additional lattice points are at coordinates ( 2 ⁄ 3 , 1 ⁄ 3 , 1 ⁄ 3 ) and ( 1 ⁄ 3 , 2 ⁄ 3 , 2 ⁄ 3 ), whereas in the alternative reverse setting they are at the coordinates ( 1 ⁄ 3 ...