Questions tagged [mineralogy]

questions relating to the scientific study and identification of minerals.

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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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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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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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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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29 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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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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37 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
43 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
101 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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61 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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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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1answer
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“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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29 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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36 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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60 views

what type of rock is this? blue/green and brown [closed]

I found this rock while up in the mountains and I have no idea what type of rock it is.
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125 views

Identification required, rock formation found whilst on holiday in Cephalonia, Greece white object embedded inside? [closed]

This rock was found in kephalonia Greece, on a beach in lassi. The rock is black in colour, smooth with thumb like prints, very metallic smell and very slightly magnetic. We took this rock to oxford ...
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43 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
817 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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50 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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38 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
19 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 ...
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1answer
93 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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252 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
123 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
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What is this translucent and blue vein crystal, 7.5 < Mohs < 9, Lustre: Aventurescence [closed]

It looks like quartz, but it has blue veins on the surface that look died. Not all surface scratches are blue though. Hardness: > 6.5. Nail file will not scratch it. > 7 quartz will not scratch it. >...
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94 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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86 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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106 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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Why would India have so much thorium on it's beaches?

The recent BBC News article Why India Wants to Turn it's Beaches into Nuclear Fuel includes the passage: The tropical beaches of India probably bring to mind sun-dappled palms, fiery fish curries ...
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310 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
91 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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78 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
72 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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1answer
312 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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Is this petrified wood or just “some rock”? [closed]

I was gifted this and have no idea what it is and was to embarrassed to ask, so here I am.
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63 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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1answer
75 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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1answer
516 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
173 views

Is this deep green calcite, green gneiss stone? [closed]

The site where it is found is characterized by schist, quartz and gneis, but also other species of rock. This is a scissors 2 cm semi transparent, vitreous luster, hard scale 6.5 - 7 ... I will post ...
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1answer
178 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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87 views

Can you help me identifying this beige/brown rock? [closed]

I found this stone in a box where I keep some memorabilia. Unfortunately I don't know, where it's from, maybe it's from a mountain side in the alpins or from a beach at the mediterranean sea. One side ...
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1k 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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44 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 ...
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185 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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200 views

Help identify glowing stone with scarab carving [closed]

I found almost no information from searching Google, Someone mentioned it might be Fluorite. I simply don't know where else to look for an answer and so I am asking you. When I was a child, my ...
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Detecting the hydrothermal alteration zones?

Is it possible to use remote sensing to determine Hydrothermal alteration zones without resorting to collecting samples from the Area of study?
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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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184 views

Which Earth minerals would Moon colonists miss the most?

In my science-based novel, Moon colonists need to return to Earth to collect some rare or absent mineral(s) Ideally, something they could derive from seawater. Which minerals might they be...?
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Iron-nickel phase in pallasite meteorites

I have recently been learning and researching about meteorite types and classification. Pallasites are mainly composed of a 'solid-solution' of olivine crystals and an iron-nickel alloy. My question ...
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609 views

What disciplines of science are used in the locating and extraction of mineral resources? [closed]

Im trying to do an assessment but I just can answer this question!