Questions tagged [minerals]

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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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154 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: ...
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1answer
98 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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Confused about the genetic term supergene mineral

I am bit confused about the term supergene on a genetic mineral classification. At this genetic clasification of minerals the author includes on supergene type "Weathering and oxidation zone". Wenk,...
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182 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 ...
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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 ...
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47 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 ...
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2answers
128 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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25 views

How to prepare sulfur crystal specimens?

I mined sulfur crystals last week and I read the following on this guide: To prepare the specimens [...] it is necessary to soak them in water to which ammonium hydroxide has been added. This ...
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38 views

Space Symmetry Groups: Wyckoff notation, diagram and positions

In the subject: "Introduction to Chemical Geology", I have given the spatial symmetry groups. At present, I know the different symmetry operators: rotation axes, center of symmetry (or inversion), ...
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60 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 ...
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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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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 ...
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112 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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292 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?
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158 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
107 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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168 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 ...
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82 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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109 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 ...
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354 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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89 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.
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1answer
354 views

heavy, brown, rock with crystals, please help identify [closed]

please help identify this rock. it is heavier than most. dark brown color. picture is shown with streak test. found in Philadelphia pa. at home demolition site. crystals seem to be different type and ...
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364 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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1answer
88 views

Unidentified mineral found in France [closed]

(I am not a native english speaker, so I'm not really aware of the specific terminology.) A few years back, I found an unidentified rock on a beach in Normandie (France). It looks and feels (texture-...
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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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56 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..
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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 ...
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1answer
582 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!
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199 views

Differentiate a rock and mineral

How to differentiate between a rock and a mineral by merely looking at it as a thumb rule?
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1answer
176 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 ...
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1answer
238 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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46 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?
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557 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 ...
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109 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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248 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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86 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.
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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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116 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
142 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 ...
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1answer
93 views

What is this rock I found being sold in a store? [closed]

I was recently on vacation in Hawaii and while there, entered a rock and mineral type store where I saw the rock below. I forgot to ask what it was while I was there and I am unable to go back and do ...
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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 ...
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60 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 ...
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663 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 ...
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1answer
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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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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?
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2k 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 ...
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1answer
866 views

What is the geologic origin of the Bauxite deposit in Bauxite, Arkansas, and could there be more?

Bauxite is an mineral of Aluminum. Despite a general mineral wealth, the USA does not have any major Bauxite deposits, except for one in Arkansas. The mining town was named Bauxite, Arkansas. The ...
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281 views

What is the geologic origin of Cryolite, and could there be more?

Cryolite is a mineral of aluminum (Na$_3$AlF$_6$). The only known natural deposit was found in Ivittuut, Greenland. It was mined from 1854 to 1987 and yielded 3.7 Mt of Cryolite ore. Basically my ...
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748 views

How gold deposits can be formed in Himalayas?

I have heard that gold is found in the water coming out of glaciers in Skardu region of Pakistan. Given that this area is part of Himalaya, what processes could result into ores of gold in this area?...