# Tag Info

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This is not a four- digit number but four separare numbers called Bravais-Miller indices. Bravais-Miller indices descrive the orientation of a crystal plane relative to the symmetry axes of a crystal, as described in Wikipedia. Put very briefly, a zero index means the plane is parallel to that axis, while nonzero indices encode the relative values of the ...

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Skarn is metamorphosed sedimentary rock, it's iron deposits are in the form of sulfides. This means two things; There almost certainly will be iron oxide contamination throughout the unit, at least I have never seen a sedimentary rock that didn't have staining from iron oxides. In my Earth Science classes we were always told that copper, and particularly ...

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Soapstone is a form of talc. It is basically talc plus other minerals, such as micas, chlorite and amphiboles, depending on the initial rocks that were metamorphosed. Soapstone is also called a talc-schist. Soapstone is formed by the metamorphism of ultramafic protoliths, such as dunite or serpentinite and the metasomatism of siliceous dolomites. The ...

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You will probably never know for sure, but the only way to get any confidence is to have any potential specimens analyzed by a mineralogical laboratory that can do Gamma spectroscopy. Fake trinitite, use a variety of means to achieve the glassy green silica look as well as mild radioactivity; however, only trinitite from a nuclear explosion will contain ...

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Quartz is a silicate at the most used Dana and Strunz classifications of minerals. Several websites and mineralogists classify it as silicate. The structure of quartz is similar to other silicates with Si-O tetrahedres. Quartz structure. quartzpage.de

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quartz a silicate mineral or an oxide mineral Both. The two are not mutually exclusive. Quartz is an oxide, because it is an oxide of the element silicon. Quartz is also a silicate, because it is composed of a framework of silicate tetrahedra.

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You might be getting sulfite (SO32−) and sulfate (SO42−) mixed up. Iron(II) sulfate is FeSO4·xH2O. As you state, melanterite is FeSO4·7H2O, which is a mineral form of hydrous iron(II) sulfate, an iron analogue of the copper sulfate chalcanthite. Various sources list the color of melanterite as being Colorless to white or green, also greenish-blue to blue ...

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Dyeing agate is a common practice- the stone is real, but it's been cosmetically altered. The stone gets soaked in a chemical solution, which is absorbed into the microscopic pores in the stone. Whatever dye the person who made these coasters used must have been water-soluble. So, yes, cold water would also cause the pigments to bleed.

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This was also asked in Chemistry Stack Exchange, where it was noted that barium sulfate is insoluble in water and generally insoluble in acids. A quick check reveals that indeed the other minerals can be dissolved in nitric acid and so should yield to aqua regia. Thus barite is the troublemaker. Barite can be dissolved in hot alkaline chelating solutions, ...

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My understanding is that soapstone is talc (hydrated magnesium silicate) which has been metamorphically transformed Not quite. Soapstone is talc-rich rock. The way you put, you had talc to begin with, then it was metamorphosed, and something happened to the talc to transform it into soapstone. This is not accurate. You had something else to begin with (see ...

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@John has answered to the second question: "Is there a natural process which removes salt from the sea at a significant rate?" This is an answer to the first one: "Is there a natural limit to this process, or the will the sea keep getting saltier forever?" Yes, there is a limit, sea water cannot keep getting saltier forever. Sea water is ...

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What you are asking about is mineralogy, a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical ...

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This is the classic description of a porphyry copper-molybdenum deposit. What happens is that there is a magmatic intrusion (the porphyry), which then solidifies. When it solidifies, it expels acidic hydrothermal fluids which carry metals in them - most often copper (represented by chalcopyrite) but also sometimes molybdenum (represented by molybdenite). ...

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Let me just add to the other answer: Plagioclase feldspar is the most common mineral in the Earth's crust. You will find it in most rocks plutonic rocks, and it is also a very common mineral in volcanic rocks. You will find it in gabbros, diorites, andesites, most basalts, most granites, some rhyolites, all monzonites, some peridotites, and list goes on and ...

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You can't really generalize like that for all igneous rock ranges. The chart actually tells you what the type and (approximate) mineral composition of a rock are as functions of the chemical composition, specifically silica content. You should be looking at how the minerals are distributed as a function of silica content. To understand this diagram fully, ...

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There are two ways (at least two I will discuss here) to date a metamorphic rock. The first is using an isochron. During a heating event, isotope ratios between different minerals (most often used are Rb-Sr and Sm-Nd) equilibrate, and the clock resets among the different minerals. You get a Rb-Sr value for several different minerals and plot them up. Ideally,...

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The main objection with regard to sedimentary rock is that you can date the individual mineral grains with isotopic techniques but not when they were laid down together. All metamorphic rocks show some degree of new crystal growth whether through melting of the existing rock or additional material being deposited by transiting geothermal fluids, often both, ...

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The short answer: cubic cleavage is a specific example of 3D cleavage. A cleavage plane is a direction along a crystal splits preferentially when exposed to mechanical stress. 3D crystals are objects where the spatial arrangement of atoms is described in a parallelepiped (a unitcell) with three outer dimensions $\vec{a}$, $\vec{b}$, and $\vec{c}$. The ...

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The quantities of oil in a deposit are listed under two categories: resources and reserves. Resources are deposits that could be converted to reserves if economic factors, prices and costs, were favorable. Reserves are deposits that can be extracted for a profit. What makes a deposit profitable involves many things: The size of the deposit The quality of ...

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No there are natural processes that remove salt as well. as sea level changes water gets trapped in basins and evaporates leaving the salt behind, this is where many of the salt formation on earth came from. whenever sea levels fall the salinity of the ocean drops. Tectonically isolated basin can remove salt in the same way. The process can even happen ...

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I highly recommend "The Story of Earth", by Robert M. Hazen. The title sounds like a children's book, but it's actually a very good starting place for learning about historical geology, which is essential for understanding other aspects of earth science. It's a very accessible look at how planets form, and it won't cost you nearly as much as the ...

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