Questions tagged [mineralogy]
Questions relating to the scientific study and identification of minerals.
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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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1answer
46 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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2answers
36 views
Feldspar content of coarse-grained igneous rocks
From the chart, I would say that plagioclase feldspar is more abundant in coarse-grained igneous rocks than alkali feldspar, as it is found in all three listed, whereas alkali feldspar is only present ...
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2answers
71 views
Quartz mineral category
Different learning resources categorise quartz differently. Strictly speaking, is quartz a silicate mineral or an oxide mineral?
3
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1answer
35 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.
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1answer
23 views
Hydrocarbon resources extension. How?
Pardon my naive question. But I heard this argument quite sometimes.
One can find at the Schlumberger careers page the particularly interesting FAQ:
“We are often told that oil is running out. Why ...
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 ...
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1answer
40 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 ...
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0answers
19 views
Identify my rock [closed]
I love to break down rocks ( specifically gravel ) to see what's in them. This rock had a pearl looking object in the center, that is surrounded by a small circle of pyrite. The small circle of pyrite ...
2
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2answers
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How does metamorphism change talc into soapstone?
My understanding is that soapstone is talc (hydrated magnesium silicate) which has been metamorphically transformed. However, it is not clear to me how this transformation affects the talc.
What is ...
6
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2answers
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Will the sea get saltier forever?
The sea wasn't always salty. It's been getting saltier over millions of years as minerals dissolve.
Is there a natural limit to this process, or the will the sea keep getting saltier forever?
Is there ...
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0answers
45 views
Why and how do quartz crystals change from cloudy/translucent to clear/transparent?
Two pieces of quartz people have given to me at different times have become gradually clear over the space of a few years. Previously they were very cloudy, translucent without any detail visible ...
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1answer
115 views
Does higher hardness means that A cannot scratch B regardless of any other variable?
You have object A of hardness 4 and glass B of hardness 6.
Is this information alone enough to determine that, under any circumstances object A will never be able to scratch glass B?
For a more ...
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2answers
110 views
What is the connection (if any) between jarosite and subsoil biological activity near Spain's Río Tinto?
In the short BBC video Spain's otherworldly red river, Ricardo Amils, a researcher in Spain's Astrobiology Center says the following (amateur transcription):
Río Tinto is a peculiar place in our ...
4
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3answers
177 views
Introduction to Geology Books
I am a high school student who is thinking about going to university for Geological Sciences. I've had an interest in rocks and such since I was little, but I want to get an idea of what studying ...
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2answers
158 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:
...
3
votes
1answer
64 views
What is the meaning of the subscript in the abbreviations of some minerals?
I have noticed that in many articles on minerals that I have read the abbreviation of some mineral has a numerical subscript, for example, occurs with the forsterite (Fo95-90, Fo92-84, Fo94, etc.). ...
5
votes
1answer
104 views
Is the association of fluorescent minerals calcite, fluorite, and apatite with fluorescent rare-Earth minerals a coincidence?
If I understand this answer and this comment correctly, minerals like calcite, fluorite, and apatite are "commonly associated with (Rare Earth Element) REE deposits", and like some REEs also fluoresce ...
2
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2answers
50 views
Ore Reserve Definition
I've seen many papers on mineral deposits say something along the line of "a 100,000 tonne deposit of Zn, 1% grade." Does this mean there is 1% of 100,000 tonnes which is 1000 tonnes pure zinc, or ...
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0answers
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mineral prospecting in Iran
I live in Iran and I want to do personal mineral prospecting for natural crystals and gemstones and beautiful minerals. Unfortunately, there are no
reliable information available. Anyone can help me ...
2
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1answer
35 views
Ore Deposit Determination
How are ore body sizes determined? What are the most reliable techniques of determining the size of ore deposits as well as their content?
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1answer
157 views
If the earth's core is made up of copper/other metals other than iron-nickel alloy, how our magnetosphere will be?
We know that our earth's core is made up of iron-nickel alloy and it is spinning to create magnetic flux all around our planet to create our life-saving Magnetosphere. And this also influences our 9.8 ...
2
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0answers
39 views
Can crystal lattices be analogue? [closed]
This question might turn out to be more about physics then geology so apologies in advance if that is the case.
Years ago I read something that said in crystals "atoms have finite positions along the ...
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 ...
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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 ...
5
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1answer
74 views
Does muscovite occur as a contact metamorphism mineral?
Does muscovite occur as a contact metamorphism mineral, with dacitic intrusion into dacitic rocks?
3
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1answer
118 views
“Obicular” structures in basalts
I found spherical or globular structures, structures in basalts of a greenstone belt which underwent alteration and deformation. However, in thin section, these structures have undeformed pyroxene and ...
3
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2answers
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Database of color wavelengths of minerals
I was wondering about the physics of color, and now am interested in finding out if there are any resources (databases, text files, html tables, or pdf listings) of minerals and their associated ...
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2answers
50 views
What does the unit cell of petitjeanite look like?
The question in Chemistry SE What is the crystal structure of bismuth oxyhydroxyphosphate (BOHP)? is about a catalyst synthesized by accident. A link in this comment points to the page https://www....
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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2answers
76 views
Can gemstones be cut into sheets? [closed]
TL;DR: Without lasers, electricity, or otherwise modern tools, could large transparent gems be sliced (like glass window)?
So I’m world building.
On this planet they have caves with enormous gemstone/...
2
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1answer
39 views
Name of majorite endmember $\ce{Mg3(FeSi)Si3O12}$
Does the majorite garnet $\ce{Mg3(FeSi)Si3O12}$ have a name?
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1answer
23 views
Does the shear modulus of silicate minerals vary significantly with changes in P and T?
I know that the bulk modulus, K, varies with pressure and temperature for silicate minerals and liquids, but what about the shear modulus? If so, is the change drastic for changes from standard ...
2
votes
1answer
148 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
317 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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1answer
131 views
Mineral identification - please help!
I'm currently writing an essay on a mosaic in the British Museum, and am unsure about which stone the frame is constructed from (pictured). I would be most grateful for help identifying it.
Thanks!
...
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1answer
198 views
Where/how people find minerals
Forever I have seen little shops here and there offer minerals like those crystals and neat shaped rocks of different kinds, turquoise and amethyst and many others and such. But I never really thought ...
3
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1answer
124 views
Do Pyroelectric gemstones really exist? Can they be found on web market?
I just got the curiosity today to know whether the gems that produce electricity non stop without an end exist, and I have found this site.
But I’m having doubts about it, thinking that it could be ...
6
votes
1answer
114 views
If the study of “minerals” is covered by inorganic chemistry
I am wondering what field studies "minerals", such as the minerals in Wikipedia's list. I keep thinking that perhaps it would be covered in inorganic chemistry (list of inorganic compounds wiki), but ...
11
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1answer
231 views
Why would India have so much thorium on its beaches?
The recent BBC News article Why India Wants to Turn its Beaches into Nuclear Fuel includes the passage:
The tropical beaches of India probably bring to mind sun-dappled palms, fiery fish curries and ...
3
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2answers
479 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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1answer
125 views
Is this a rock with metal or gold? [closed]
I found these really hard rock while i was excavating. It caught my attention the different colors.
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1answer
151 views
What kind of purple stone is this? [closed]
I found this stone and I do not know what type of stone is this?
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1answer
77 views
Please identify- no origin known but given to me by a geologist [closed]
A very dear man who love his job as a geologist gave this to me. He’s been all over the country so I have no idea where he may have picked it up
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0answers
153 views
Can you help me identify my rock? [closed]
I found this rock in my yard. Can someone please identify it for me? I’m not sure if you can see the blue hue on the rock in the picture! (https://i.stack.imgur.com/cuklH.jpg)
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2answers
2k views
What exactly are enantiotropic and monotropic polymorphic transitions?
Recently, I've been studying the subject of polymorphism and met two important concepts, the monotropic and enantiotropic polymorphic transition types. However, I can't really seem to grasp the ...
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1answer
213 views
Why would CaO be more finely spread than K2O in Granodiorite?
I recently interpreted some XRF data on samples of a granodiorite which were classified under three different types of physical characteristics: very little, mild and significant levels of weathering. ...
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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
52 views
Is there any rule of thumb to decide the indentation hardness test?
How to decide whether Brinell Hardness test, Rockwell test or Vicker's test is to be applied as far as grain-size is concerned? Is there any rule of thumb to decide the type of indentation hardness ...
3
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1answer
232 views
Differentiate a rock and mineral
How to differentiate between a rock and a mineral by merely looking at it as a thumb rule?
