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why are the crystals in the my teacher sayz its because
during the cooling process,
the outside cools faster than
the inside, bla bla bla, but i
dont get it:-(
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The crystals in geodes are precipitated from water that infiltrates into the hollow cavity underground where the geode will form. Usually the crystals are made of quartz, a mineral which can precipitate directly from molten magma but can also be carried in solution in water underground, which is the case for geodes. The crystals start to grow on the surface of the cavity, and begin as many small ones. As time goes on and the crystals grow larger, some of them crowd out the slower growing ones around them. As this happens the ones that survive continue to get bigger, and because they are all growing toward the center of the geode, they will be larger toward the center because they have had longer time to grow in that direction. |
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Would anybody want to trade a |
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I would but I dont have your webkinz username so I couldn't mail it to you in webkinz. |
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Why is Geode sedimentary I always wondered why Geode is
sedimentary chemical. It has
very large crystals and it
looks like it has to be
igneous intrusive. Can you
explain to me in detail why
that is?
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Geodes form by precipitation of minerals from solution. That would make it a chemical sedimentary rock. They are not often found in intrusive igneous rocks because the geode needs a vug, or a cavity within the host rock in order to form. Intrusive igneous rocks rarely have vugs, but do sometimes have large fractures or joints that can be crystal lined similar to a geode. Geodes are more likely to be found in extrusive igneous rocks that have vugs formed by gas that comes out of solution as the rock cools rapidly (in comparison to intrusive igneous rocks). These vugs eventually may fill with fluid which carries dissolved calcite, quartz, and other minerals. As the fluid becomes oversaturated different minerals will drop out of solution forming layers of the geode and finally forming crystals within the center of the geode. The similar things that form in sedimentary rocks are often referred to as concretions, and these are seldom hollow. They may be composed of calcite, chert, or other minerals, and will often have concentric rings within them. However, they do not form within a vug or cavity, but instead appear to grow outward. Septarian concretions have crystalline filled fractures inside them that makes them quite attractive. Concretions appear in most cases to form from a nucleus and grow outward, unlike a geode's growth inward. |
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where can i find the AMD i am interested in the NX
model. i have looked all over.
newegg, nextag. is this thing
even available for a hobbyist
like me?
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http://cgi.ebay.com/AMD-Geode- NX-1750-K7-S462-S-462-CPU-PROC ESSOR-Pro-3000_W0QQitemZ320208 807751QQihZ011QQcategoryZ15919 QQssPageNameZWDVWQQrdZ1QQcmdZV iewItem http://cgi.ebay.com/RG049AA-HP -Compaq-t5725-Thin-Client-AMD- Geode-1500_W0QQitemZ1501995877 01QQihZ005QQcategoryZ11221QQss PageNameZWDVWQQrdZ1QQcmdZViewI tem |
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i want to sell my large the smokey crystal quartz is
roughly 12" by 12" by12" and
weighs about 35 kilos and the
geode is 18"long by 6"wideby6"
high and weighs around 15
kilos and the amethyst stones
are almost black
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A rock and mineral shop might. A university might as well, though geology departments tend to be poor. You can always try eBay or if you don't have eBay in Australia, I am sure there is some other online selling platform. Smoky quartz isn't worth too much and I'm not sure how much you could get for amethyst that isn't a nice, bright purple. |
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