Questions tagged [minerals]
The minerals tag has no usage guidance.
77
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Term for the Process of the Early Earth's Crust's Changing Mineral Composition
In the book, Story of Earth-The First 4.5 Billion Years, From Stardust to Living Planet, by Robert Hazen, Chapter 3: He discusses the changing mineral composition of the early Earth's crust from ...
2
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1answer
34 views
How to identify chemical property and structure of rocks?
I am interested in identifying the properties of rocks. For example, black opal is shiny and can emit 5 different colors based on different lighting conditions. Is there a way for an amateur to be ...
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0answers
21 views
Ore prospecting and the low-hanging fruit effect
I'm trying to acquire an understanding of how the difficulty of prospecting for useful ore has increased over historical timescales.
Intuitively, I would expect that centuries or millennia ago, you ...
1
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1answer
45 views
Ore Deposit Identification
What type of ore deposit does this rock best represent?
A rock with a porphyritic texture is cross cut by a stockwork of
quartz veins. Bordering the veins is extensive alteration of the host
rock. ...
3
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1answer
34 views
Cleavage of minerals
What is the difference between 3-dimensional cleavage and cubic cleavage?
I think, they are the same, but I am not sure about if I was right or not.
3
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1answer
51 views
How can the 'crystal cleavage' of apatite have a four-digit number?
On Wikipedia's page for apatite, the crystal cleavage is listed as [0001] or [0101], which I assume are Miller indices....
But how can there be four numbers/digits instead of two, like there usually ...
4
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4answers
89 views
How is it possible for rocks to be trapped within another type of rock?
More specifically, I would like to know how the rocks in these pictures have formed:
If this is because magma has melted and trapped the other rocks inside, do they have a different melting point ...
1
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1answer
39 views
What causes dye to bleed from an agate stone?
I came across this review on Amazon. The cold drink was placed on top of the agate stone and the dye bled and left a permanent mark on the table.
Why does this happen? Is it because of the ...
3
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0answers
27 views
Looking for videos/GIFs of petrification/permineralization
Do you know of any good animations, videos, or GIFs of petrification/permineralization? For some students verbal and written explanations don’t work, they don't always visualize well. So it’d be ...
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1answer
89 views
Have fossils ever been found in the asphalt lakes of Trinidad and Venezuela?
La Brea tar pits in California are the result of ancient oil seepages and famous for the fossils of extinct animals which were trapped in the tar. The asphalt lakes in Trinidad and Venezuela are also ...
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2answers
157 views
How to genetically classify a mineral resulted from weathering?
I am writing a mineral guide for smartphones which classifies minerals according to their formation environment.
From sugestions on this related question, I changed the classification to:
...
4
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1answer
103 views
History of the Arctic Ocean
Much of the Arctic Ocean is fairly shallow compared to other oceans. There must have been times in the past during severe ice ages that a lot of what is now the ocean bed was above sea level. When was ...
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2answers
202 views
Can I just walk around Greenland with a UV light and find rare Earth minerals on the ground?
The NPR.org news article and podcast Greenland Is Not For Sale. But It Has The Rare Earth Minerals America Wants is interesting, and it includes a few large GIFs (too large to post here) that appear ...
3
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2answers
93 views
Database of mineral with images for a neural network application
I'm diving into data science and I'm looking for a complete database of minerals. I downloaded the csv file from http://rruff.info/ima/ . It contains 5516 lines of data but it does not have images or ...
3
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1answer
50 views
Hyperspectral Detection of Ore
How can I use hyperspectral satellite imagery to remotely detect copper or any prespecified mineral deposit in general?
Where can I find a database of the absorption and reflection bands of various ...
2
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2answers
133 views
Is this classification of mineral formation environments correct?
I am writing an app for students that consist in 180 sheets of the most common minerals on Earth's Crust.
One of the fields of the sheets is environment of formation.
It is important to me to ...
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2answers
64 views
Chloride ions for the salty seawater
Where does the chloride ions that are required for the salty taste of sea water come from ?
I know that it is the weathering caused by the slightly acidic (due to dissolution of CO2 with water) rain ...
3
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1answer
2k views
What's the difference between cleavage and fracture?
I see both terms refereing to fractures on crystals or minerals, so I wonder if they could be considered synonymous.
If no, what's the difference between both terms?
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0answers
13 views
Why do allophane soils behave as gels?
It is notoriously difficult to determine the texture of soil containing allophane and immogolite. According to the literature this is because the clay fraction "behaves as a gel", i.e. it's not ...
2
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1answer
147 views
An oblique-square-prism crystal?
Does any mineral crystallize in the shape of an oblique square prism? If so, what crystal system (monoclinic, cubic, hexagonal, etc.) would such a mineral fall under?
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2answers
312 views
How are minerals classified?
What exactly is done to classify minerals in Earth Sciences such as Geology? How can it be known if one mineral is the same as another if they should be visually different?
2
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1answer
299 views
How salty can snow/sleet be?
Can enough salt particulates be in the air to create salty snow or ice that is undrinkable?
Will ice form in sub zero temperatures through condensation in salty air?
1
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1answer
163 views
What is cluster situation with respect to sand mining?
Guideline on handling cluster issues : The original Environmental Impact Assessment ( EIA ) notification does not provide for the procedure to handle cluster situation, which has been proposed in ...
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1answer
273 views
Preservation of clay items
I have a general question which may sound naive: archeologists eg in Ancient Greece take a lot of information from preserved pottery they found. What physical attributes of ceramic items made of clay ...
2
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1answer
113 views
Where to start searching to find more radioactive minerals?
I'm pretty new to all this...
I've recently purchased a Geiger counter, and am hoping to locate rocks like pitchblende and other radioactive minerals for my collection.
I'm based in the North West ...
0
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1answer
120 views
I need help with these geode like rocks [closed]
I found these rocks in my pasture and was excited because I thought I had found some geodes. The rocks were in a sandy bank and looked like eggs sticking out of the bank. I am located in Ness County ...
3
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2answers
478 views
I found this strange spherical stone in Gillette Wyoming. I have no idea what it is. Please help. [closed]
These are recent pictures of it. It’s heavy, I see small minerals that catch the light in it, very bumpy, spherical, doesn’t seem to be magnetic, I was falling down a deep trench and kicked it up at ...
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2answers
165 views
What is this stratefied limestone sphere?
What is this stone from the alps of provence?
It's two spheres, one of them is made of at least 25 layers.
5
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1answer
476 views
How does palingenetic fusion occur in rock?
As far as charnockites are concerned, granitic charnockites are formed due to palingenetic fusion and metasomatism, while granulitic charnockites are formed due to high grade metamorphism.
When I ...
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0answers
56 views
Identifying rocks, minerals [closed]
I am sorry to bother you.. before passing away, my grandfather gave me a special box that contained all types of beautiful, colorful rocks and minerals. I am having a hard time identifying them! Could ...
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0answers
59 views
Please help me with the identification of this rock
What is it? It has what looks like white glitter its ugly dark brown and some orange heavy..
2
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2answers
2k views
Melting point of minerals
Looking at this website, I can see the melting point of the following minerals: http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/meltrock.html
Apparently at a temperature of 1200 °C, all the ...
5
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1answer
1k views
Why is streak different from color?
Many minerals have a streak that's surprisingly different from it's outward color. Why is this? What causes the optical properties to change if the mineral is powdered?
Thanks!
3
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1answer
231 views
Differentiate a rock and mineral
How to differentiate between a rock and a mineral by merely looking at it as a thumb rule?
5
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1answer
223 views
What are the cubic formations found inside Larimar gemstones?
I recently noticed what appears to be common cubic formations just beneath the surface of Pectolite (Larimar) gemstones. They quite resemble transparent sugar sprinkles. Each formation isn't perfectly ...
5
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1answer
539 views
Difference between pyrite oxidation and dissolution
I've seen papers use oxidation and dissolution of pyrite. Are these two processes the same? I was always under the impression that pyrite does not dissolve easily. What is the difference between ...
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0answers
47 views
Pyrite oxidation
How much pyrite has to be oxidized to produce a sulfate concentration of 15 mM?
If the solution initially has a pH of 8, roughly what would the pH drop to if there is no buffering of acidity?
3
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1answer
606 views
Saturation Index clarification
I have a problem with my project and I was hoping I would find some clarification.
I did some modeling with phreeqc to calculate saturation indices and found that calcite was saturated in an ...
5
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2answers
117 views
Sulfate salts of magnesium and sodium
What concentrations of magnesium, sodium and sulfate are needed to precipitate solid MgSO4 and Na2SO4 (let's say evaporation is occurring in a system) I'm assuming probably really high because they ...
0
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1answer
364 views
What kind of stone is on this photo
Does anybody know what kind of stone this is?
Thanks alot in advance
Wolfgang Adamec
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1answer
90 views
Satellites minerals finding capability
Just wondering with the latest satellites currently available, is it possible to locate gold which is buried under 200 ft? what is the maximum depth that satellites can look for such minerals.
3
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0answers
145 views
Dolomite and calcite precipitation
In an engineered wetland, there is groundwater flow from an aquifer with a chemical composition that is rich in magnesium, calcium and sulfate. We are finding that the aquifer is consistently ...
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2answers
151 views
Limitations on mineral precipitation from solution
If the solubility constant for a mineral is exceeded and, thermodynamically, a mineral is favored to precipitate in solution, are there any factors that may limit this from happening? Perhaps kinetics?...
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3answers
189 views
Why does Australia have no chrome?
I've been trying to collect resource data about Australia for a few years. Some good reference sites are AustraliaMinerals.gov.au and AustralianMinesAtlas.gov.au
Australia seems to be pretty rich in ...
3
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3answers
2k views
Dissolved minerals
I have a question that I am confused about.
If a mineral (say limestone) was added to a groundwater system, say like an aquifer and is completely dissolved in solution, can it ever be a solid again ...
4
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1answer
76 views
Is there a table with decomposition temperatures of common minerals?
I am about to perform a Loss On Ignition test on a material I know that contains among on things kaolinite, which will release water at 500 $^oC$. However, I tried finding a table with decomposition ...
0
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1answer
851 views
Why does halite have a cubic crystal
Why does mineral halite has a cubic crystal ? Is this a result of the way by which sodium ions and chloride ions are held together ? And what is the relation between the cubic crystal of halite and ...
3
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1answer
79 views
What causes this white coloration of the ground in Gilf-Kebir?
It seems, these white blotches are reflective enough that they caused oversaturation of a spot of image taken from a satellite at the L1 lagrangian point (click to open at max resolution, the purple ...
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2answers
2k views
Why are most minerals so rare?
There are 4,660 known minerals, so why are most of them so rare?
Is it to do with the structure of minerals?
3
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2answers
3k views
Are there any areas on Earth with purplish-colored soil/sand/rock/land?
This sort of comes from my related question, but only sort of. Are there any areas on Earth with purplish-colored soil? The purple tint would come from some mineral, perhaps deposited by rivers or ...
