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The science comprising the study of the rocks Earth is composed of, and the processes by which they change. Some subfields of geology are petrology, mineralogy, and geophysics.

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Could unconformities be a tool for preparing a geological timescale?

Unconformities subdivide different strata of rock. However such a thing could only bear the temporary scenario of the depositional beds. Then how far it could be useful to build a whole geological ...
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38 views

If the earth were completely smooth and covered in water, what would occur with ocean waves?

Related to this post: If the Earth were a smooth spheroid, how deep would the ocean be?
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21 views

Mineral identification; black & metallic

During a recent trip to the Portuguese island of Madeira, I found a couple of interesting rocks on a beach. Both the rocks pictured in this question contain the same black mineral. I first guessed ...
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1answer
45 views

Help me figure out what this purple rock is

I found this in the ground at a job site in blue springs mo . Its purple with darker purple lines through it like growth marks on a tree. It is about the size of a large loaf of bread 7 inches across ...
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Geological work of rivers and glaciers [on hold]

I'm new to new this platform of Earth science, I'm studying for an entrance exam in geology in my country. I wish to learn through this stack exchange also. Thanks... Question: what would be ...
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1answer
31 views

Can someone help me identify this crystal

So the actual rock looks black but I put it up to the light n I see green n black.... can you help me figure out what it is ? my grandfather gave it to me years ago n I’d like to find out more about ...
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1answer
131 views

Why do some earthquakes and volcanoes occur within plates?

I know that volcanoes and earthquakes occur on plate margins. But, do some of them also occur within plates?
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59 views

Why are the mountains predominately grey or dark brown?

Observing many photos of mountains one can assume that most of the mountains are grey or brown. See also the mountain article at Wikipedia. There are however several ways a mountain can form, which ...
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25 views

How to Interpreted SEM-EDX result? [closed]

I am new for SEM-EDX but I want to learn. In the EDX data result, there are Wt % and at % from every element (for Example if : Wt % C 14.16, O 51.22, Al 2.22, Si 30.64, Fe 1.75 and At% C 21.11, O 57....
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Is it possible to create clouds by pumping water into volcanoes?

Suddenly, there is this idea in my mind that if an important effect of global warming is rainfall reduction and drought, is it possible to use volcanoes as water vaporizers (regardless of costs)?
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1answer
34 views

What is this heavy rock having gold-olive colour and tiny gold coloured crystals?

The rock is very heavy, about 1.2 kg and 5 inches (~ 13 cm) long, gold–olive colour. The back has tiny gold coloured crystals and the front has bigger ones as seen in the picture. I don't really know ...
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Identify Crystal [closed]

These are pictures of petrified wood just wondering if you could tell me what the round fools Gold looking crystals are I know the yellow crystles are Amber and was told the round Fool's Gold looking ...
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What can one come to know about a mineral just by knowing name

I have been busy learning the components of various minerals for upcoming test....is there any way to predict the components or properties of a mineral just by knowing it's name? Eg: albite,augite, ...
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50 views

Is this a fossil

It this a stromatolite fossil? If it is, it’s probabaly at least 1 billion years old
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44 views

What kind of rock is this? Green

Just wondering what kind of rock this is
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46 views

I found this huge rock crystal by the river have no idea what it is?

![crystal rock yelowish to red yellow to orange has 3 layers of crystal )
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36 views

How big does something have to be to cause an atmospheric event upon entry to the Earth's atmosphere?

The question is about a foreign object, ranging from an asteroid to a spaceship. How large does it have to be in order for its presence to start messing with the weather patterns, causing the like of ...
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60 views

What kind of gem is this

I had got this as a kid and I am wondering if it is worth anything.
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1answer
32 views

Does crustal thickness have anything to do with how life existed and sustained on Earth? [closed]

The original question that was put on hold "If the crust were the thickest layer of Earth, what effect would its thickness have on organisms?" was actually one of those 'counterfactual question' ...
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1answer
48 views

How does this melted-wax erosion pattern form in sandstone?

How does this kind of erosion pattern that looks like melting wax form in sandstone? Can you describe the kinds of processes and kinds of rocks that are needed for this? I've seen it in Nevada, but ...
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Please Help Identity this Rock (Maybe a hand tool or weapon)

This rock is very heavy for its size, it also seems to be very hard. It fits perfectly in my hand as if it was made to rest there. It was my moms rock that she gave me before she passed away from ALS.
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What would cause a rock to fracture to a central point?

I found a rock that appears to be a fragment of a fairly spherical rock. The original outer surface is knobby, while the broken side has ridges radiating from a central point. (See photos.) What ...
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1answer
77 views

What on Earth in can repel a magnet? [closed]

The iron in blood is naturally repelled by a solid magnet the opposite of iron outside of blood by a magnetic field and I wander... Are there any elements that are repelled by a solid magnet? https://...
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35 views

Identifying rocks, minerals

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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ALOS Palsar SLC data products for geological mapping

I have some ALOS palsar SLC data products which are downloaded from ESA database and they are processed with ESA ALOS-PALSAR IPF processor which is different from JAXA. Formerly it was not possible to ...
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33 views

Metallic rock identification from Ontario Canada

This rock was found in Lake/Lac Clair near Sturgeon Falls Ontario Canada in about 2 feet of water next to the edge of the lake. It can easily fit in my hand. You can see a size comparison in the ...
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Is an underground mine collapse or a tunnel collapse called a sinkhole?

Imagine there's an underground man made structure e.g. a tunnel or an underground train station that collapses creating a depression in the surface. Would that technically be called a sinkhole? What ...
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41 views

Gem identification

I received a bunch of stones from my Grandfathers mineral collection but i’m unable to identify some myself. I’m not certain if this stone is a rose quartz. It’s about an inch long and has some kind ...
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1answer
59 views

Dark heavy rock

I found this dark heavy rock near Wombeyan Caves NSW. Australia. It is 9 by 6 cm and weighs 353g; it is not magnetic and was found in a dried up riverbed.
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1answer
27 views

I need help to identify this Stone [closed]

I would like help to identify this Stone. I have found a large amount of these stones in my yard. I would just like to know if they are worth anything or if I'm just going to have a pretty driveway
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1answer
106 views

Are these obsidian snowflakes?

I'm not sure if these are obsidian snowflakes: I found it near a river, hardness is 4 to 5, it has a wax lustre when pre-polished. The 'flakes' in the matrix are raised and gray. Pre-polished side ...
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1answer
73 views

Can someone identify this geode found in upstate NY

Can some identify this geode? It was found in upstate New York in a flat sandy plain 1/4 away from the Hudson River. The geode is approximately 3" long, brown exterior, 1/4" "shell" gray , and 1 1/2" ...
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2answers
2k views

What is the average color of dirt?

Where I live the soil is red. Is there a map or chart where you can see the average color of the dirt according to geographical location? What would the color be if all of the dirt on Earth was ...
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1answer
52 views

What kind of stone is this?

Years ago, I bought from a flea market two strange looking stones, that the owner said he had found under the sand of a dune in the desert (I don’t remember which). Maybe it’s true, maybe not, but I ...
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1answer
85 views

At what depth does the underground begin to warm up?

Spring water comes out colder from being underground. But if you get deeper the temperature goes up. At what depth does the underground stop getting colder and begins getting warmer? Is there a map ...
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1answer
91 views

Is this deep green calcite, green gneiss stone?

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
35 views

How does the synthesis of Kaolinite (and it's by products) influence porosity in granodiorite?

I started studying the effects of weathering on granodiorite (see previous posts) and plan on referencing the link between the chemical weathering of feldspar plagioclase leading to kaolinization, a ...
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1answer
47 views

Can someone help me identify this rock please?

I recently found this at a garage sale and I would love to know rock this is. It weights 6 lbs. -Thank you
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3answers
116 views

In an Earth-like planet with no history of carbon-based life forms, would there be limestone?

The extent of my understanding of limestone is about what Wikipedia says at the very top of the page: Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such ...
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What kind of stone or gem is this

My dad found this on one of our many prospecting trips. Usually went for gold but must have picked this up because he thought it was interesting. It sat covered in dirt in my garage for 20 years. ...
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1answer
40 views

Please help me identify these two rocks? [closed]

Two rocks both green, one is transparent, the none transparent rock is extremely tough almost impossible to cause a scratch on it. Thanks
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1answer
58 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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42 views

Help identifying rock?

Found in stream, heavy, has a tin of red lines and dark. 1]]2[grey white, rusty ]3. Dark lines n rusty lines. Hard to break off piece ain't magnetic
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What are those flat areas in this desert formation seen from orbit? [duplicate]

(Google Earth at 19°58'49.87" N 53°38'09.51" E) Related to: What produces these distinct shapes in the Rub' al Khali seen from space? What is the flat (?) green/blue-ish terrain in between the ...
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1answer
52 views

What other graphical methods can be used to represent weathering?

Context: For one of my reports I have taken samples of a rock from an adjacent creek. I have done XRD analysis to get compositions of calcium, potassium and aluminium. My question: I know about ...
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1answer
90 views

Ocean water coming from Mantle vs coming from meteorites

Posibly duplicate from Water on Mars and Earth I remember well a hydrology course where our teacher made some calculations of the total flux of water from Mantle ejections in Earth's history. He ...
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1answer
27 views

What's a reasonable flow rate/mass flux for a fumarole?

Obviously, there is going to be a large amount of variability, but what are some realistic values?
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1answer
60 views

Can someone identify this 'striped' stone? [closed]

The stone has a raised texture on the top where the stripes are. I'm not sure exactly where it was found. It is not magnetic.
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2answers
67 views

Why do the earth sciences use mega-annum instead of mega-year?

I've noticed that geology and related fields use mega-annum (Ma) instead of mega-year (Myr) as the unit for 1 million years. Why is that? Is an "annum" different from a "year" in geology?
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Is there a large undersea caldera in the Azores?

There looks like a large undersea circular feature (Google maps) about 120km across with its north edge on Sao Miguel Island and its south edge on Santa Maria Island. Has any work been done to say ...