Questions tagged [mineralogy]

Questions relating to the scientific study and identification of minerals.

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34 views

Isotopic dating of metamorphic rocks

I read in my physical geology textbook that sedimentary rocks cannot be dated using isotopic dating, because they are formed from fragments of other rocks and minerals, which if you were the subject ...
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34 views

Why were Fe-oxides not usually used for finding skarn Fe ore deposits in geochemical exploration?

I found that Fe-oxides were usually not used for vectoring Fe mineral deposits of skarn type in geochemical exploration. As an indicator element, the common practice told us Fe-oxides should be the ...
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Identifying metallic element or compound in murine clay

I have been doing a lot of digging in a thick murine clay as part of a construction project. In the course of doing this work, we noticed significant bands and streaks of blue color in the clay, which ...
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35 views

Artifical Ore Genesis?

From my understanding, the formation of ores can be reduced to a simple three-step process of the removal of minerals from a source via some mechanism, the transportation of these minerals, and ...
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1answer
100 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 ...
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69 views

What kind of rock is this? [closed]

A few years ago in Venezuela, parque nacional de Cainama, the tourist guide found and gave me this rocks, he told us that a geologist told him that those could be radioactive but no one believed him. ...
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1answer
44 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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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. ...
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2answers
43 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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74 views

Quartz mineral category

Different learning resources categorise quartz differently. Strictly speaking, is quartz a silicate mineral or an oxide mineral?
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122 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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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 ...
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1answer
63 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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52 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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1answer
101 views

Are there any sulphides, sulphates, carbonates that cannot be dissolved by aqua regia?

I was looking into these specific minerals: arsenopyrite, pyrite, chalcopyrite, barite, calcite, dolomite. I investigate issues with tellurides not showing expected gold concentrations. There is gold ...
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2answers
43 views

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 ...
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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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102 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
134 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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113 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 ...
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3answers
210 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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161 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
68 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.). ...
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1answer
164 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 ...
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52 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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33 views

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 ...
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36 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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224 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 ...
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41 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 ...
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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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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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77 views

Does muscovite occur as a contact metamorphism mineral?

Does muscovite occur as a contact metamorphism mineral, with dacitic intrusion into dacitic rocks?
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1answer
127 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 ...
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101 views

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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51 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....
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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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84 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/...
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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
173 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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478 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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Formation of Hematite on Mars via Perchlorates as an Oxidizer

Hematite on Mars is generally thought to have formed either in pools of water or from volcanic activity. A comment to the answer to the question: How do hematite and magnetite form? states that ...
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1answer
211 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 ...
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132 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 ...
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115 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 ...
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278 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 ...
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532 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
138 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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180 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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3k 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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219 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. ...