Questions tagged [minerals]

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4
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2answers
87 views

Are there minerals that can't scratch each other but have different hardness on Mohs scale?

So I was reading here that Mohs scale is not transitive and therefore could not overcome the comparative phase in order to be turned into a measurement procedure. As it is written in the webpage, &...
2
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1answer
88 views

Avoiding fake trinitite

I would like to get some trinitite for my rock and mineral collection. The problem is that there is apparently a lot of fake trinitite for sale in the internet. How do I avoid the fakes, and be sure I ...
2
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1answer
78 views

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 ...
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1answer
40 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
23 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
49 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
82 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
57 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
93 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
46 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 ...
0
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1answer
113 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
160 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
104 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 ...
6
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2answers
215 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 ...
4
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2answers
106 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
136 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
66 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
163 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
399 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
321 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?
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1answer
173 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
294 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
125 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 ...
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1answer
126 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
513 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
180 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
512 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
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
248 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
236 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
575 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
51 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
617 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
120 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 ...
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1answer
462 views

What kind of stone is on this photo [closed]

Does anybody know what kind of stone this is? Thanks alot in advance Wolfgang Adamec
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1answer
92 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
146 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
172 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
216 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
82 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
898 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?