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GeoPicture of the Week: Amazing Rhodochrosite

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  Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. Rhodochrosite occurs as a hydrothermal vein mineral along with other manganese minerals in low temperature ore deposits as in the silver mines of Romania where it was…

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GeoPicture of the week: The Mexican hat

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When you look at these rocks – it’s quite easy to understand why they’re usually called ‘The Mexican hat’: The Mexican hat is a rock formation in south-central San Juan County, Utah, United States. Interestingly, it’s the name of a mini-village (named after the formation), with 31 people inhabiting it. The formation is a 60-foot (18 m) wide by 12-foot…

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GeoPicture of the Week: What Causes the Colour of Gemstones

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You may have wondered exactly what is it that makes gemstones so brightly colored, and if you were curious enough to actually pursue that question, you found out that it’s all chemistry. This picture explains it: Most minerals are actually colorless in their pure form, and they are colored by impurities. The color itself is caused by the different absorption…

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GeoPicture of the Week: The Lion Rock in Sri Lanka

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The Sri Lankan lion rock (Sigiriya) is an ancient palace of archaeological and geological importance. The site is dominated by a massive column of rock nearly 200 metres (660 ft) high. According to the ancient Sri Lankan chronicle the Culavangsha, this site was selected by King Kasyapa (477 – 495 CE) for his new capital. He built his palace on the top…

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GeoPicture of the Week: Geologic Faults

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This picture from Cornell University really encapsulates the beauty of a geologic fault – it’s like someone took it from a text book and slammed into real life. In geology, a fault is a planar fracture or discontinuity in a volume of rock, across which there has been significant displacement along the fractures. You can see how the different layers (strata)…

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GeoPicture of the Week: Perfect Pyrite cube

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  Quite an awesome picture of a single pyrite crystal, isn’t it? I always find it fun that when they see something like this, most people don’t think it’s natural, that it’s somehow man made or at the very least cut by man – but that’s not really how it works. Pyrite usually forms cuboid crystals, and sometimes they are purely…

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GeoPicture of the week: Uvarovite, an uncommon type of garnet.

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Garnets are a diverse group of minerals, most of which vary in color from brown to black-ish. Uvarovite however is a deep green, really lovely to look at. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. Here are some remarkable pictures of other garnets:        ……

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GeoPicture of the week: Mind blowing Bismuth

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This is Bismuth – it is a natural chemical element which chemically resembles arsenic and antimony. Elemental bismuth may occur naturally, but this form does not occur naturally – it was developed in a lab. Still, it’s just mind boggling how beautiful it is!……