Questions tagged [rocks]

Questions about rock types, formation, chemistry, and physics. If you just want help identifying a rock please use the tag "identification-request".

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11
votes
2answers
293 views

Can rocks have pressure signatures?

Since rocks can have magnetic signatures, as is the case with paleomagnetism, can they store past pressures also? For example, when researchers are trying to determine past ocean levels, they ...
0
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1answer
84 views

What kind of rock is this?? White rock [closed]

What kind of rock is this?? Found laying on the surface of gravel.
3
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2answers
109 views

Odd Inuksuk-like objects

I found some huge objects that are way too big to be inuksuks, in my opinion. The object on the right is very odd because the arms are not straight like they are in most images of inuksuks. and ...
5
votes
3answers
273 views

Making a local geological field trip an interesting and educational event for children?

I have no expertise in geology or earth science, but I would like to do a "field trip" with my home-schooled young children (under age 10) where I could teach them about geology from a hands-on ...
3
votes
1answer
175 views

What kind of rock or stone is this? Where did it come from? [closed]

I found this on the side of the road in Oregon, i think it was left or forgoten about thats why it was left there but it has crystal pockets, multiple colors, some smooth sides, perfect circles and ...
1
vote
0answers
100 views

What a place that sells rocks is called [closed]

If a nursery sells plants, I'm wondering what a place that sells rocks is called. Something where they offer rocks of various sizes like this: Well, those are all river rocks, but I'm wondering about ...
0
votes
1answer
115 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 ...
3
votes
2answers
435 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 ...
1
vote
1answer
114 views

What kind of purple stone is this? [closed]

I found this stone and I do not know what type of stone is this?
4
votes
0answers
657 views

Definitive values that classifies a rock as having “low”, “medium”, and “high” -strength, -hardness, -toughness, and -consolidation?

Question: Are there any widely accepted published values (or ranges) that classifies a rock as having “low” “medium” “high” -strength, -hardness, -toughness, and -consolidation (cementation or ...
1
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3answers
455 views

Can anyone help me identify these rocks please? [closed]

I apologize for any errors in my pictures or writing. My first post. [
2
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0answers
70 views

Whats this stone? [closed]

Found it couple days ago and it amazes me how smooth the surface is but cant identify it please help me. Found it in north germany near a lake on a trip there.
0
votes
2answers
252 views

What type of yellow-green stone is this? [closed]

It's greenish yellow with white. Got it in a mixed stone package from Amazon. No luster, I'd say a 7 in hardness, it doesn't look homogeneous.
3
votes
1answer
167 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 ...
1
vote
0answers
56 views

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 ...
1
vote
0answers
70 views

Rock / Fossil ID? [closed]

Please see link below if anyone can help ID. I think the little claw looking thing is a fossil? The red rock is smooth,Matt in some places and semi glossy on some of the sides. The black rock has ...
0
votes
1answer
56 views

Rock identification ? What kind of it is? [closed]

My co-worker had this rock and told me found just behind the store, Big R, and put on the table in the office. Location is Trindad, Colorado.
11
votes
2answers
3k views

Zeolites, odor control, and the witchcraft of sunlight

Various companies offer "volcanic crystals" or "volcanic rock" available in small mesh bags for odor control. The best description I have found is that these are made up largely of Zeolites. All of ...
1
vote
1answer
60 views

Help identifying rock? [closed]

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
1
vote
0answers
99 views

I found this rock on Laguna Beach [closed]

Rock found on Laguna Beach. It is not sand stone and is heavy for its size 3" x 2". It is rather dense. Click the image for full size:
2
votes
3answers
704 views

What is meant by intraplate volcanism?

I am having massive confusion on whether intraplate volcanism refers to volcanism occurring at plate boundaries or away from plate boundaries (such as formation of ocean island basalts), or perhaps ...
1
vote
1answer
1k views

Is this platinum ore? [closed]

Was found in central Mexico. It's very metallic, shiny, showing some streaks of gold and quartz.
3
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0answers
323 views

Puzzle using relative dating principles

This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here. Here is what was told: -"Worms" (curved ...
2
votes
1answer
455 views

Inorganic Limestone and Inorganic Gypsum

I read that limestone is made from the compaction of marine animals' bones. But, I am unable to find out why limestone could not have been produced from calcium occurring naturally (5th most abundant ...
1
vote
1answer
535 views

Oldest to Newest Bedrock in the USA “road trip”

I am supposed to design a road trip (using major highways) across North America. I have to design a route that starts with the oldest rock of Archean age and finishes with the youngest rock of ...
3
votes
2answers
1k views

Radon is a naturally occurring radioactive gas. How does this work?

Radioactive rocks can release a gas called radon when they decay, which can build up in the basements of buildings with serious effects on people's health. Does anybody have information on how radon ...
1
vote
0answers
76 views

I was wondering if anyone could help me identify this rock [closed]

I found this rock along with a few other very similar ones. I found it on an island in Croatia.I was wondering if anyone could tell me the name of the rock.
6
votes
2answers
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?
0
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1answer
67 views

What is the definition of “ground-up shell”?

The archeologists use the term "ground-up shell" to designate a type of temper used for pottery. What is this material? Earth containing fossilized mollusk shells? I noticed the term is also used in ...
13
votes
1answer
9k views

How are giant sinkholes filled up?

There are a few impressive photographs of giant sinkholes that appeared in cities, such as this one: However, followup information (e.g. Guatemalan sinkhole) or photographs on how these kind of ...
3
votes
2answers
274 views

A few questions about glass

A glass, as I understand it, is a material whose solid phase is amorphous and which undergoes a glass transition when heated. My train of thought - and therefore my questions - began with obsidian. ...
1
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0answers
74 views

classification of oil shale

Could we classify oil shale as a biochemical sedimentary rock ? Oil shale is a muddy rock contains Kerogen. So I think in oil shale to be a mixture of Kerogen and mud sediments, and that's not the ...
3
votes
2answers
1k views

what is a transverse isotropic rock?

I know isotropic means equal properties in all directions , but the term "transverse" is not making it easy for me to understand.
6
votes
1answer
915 views

How can a non-geologist identify a rock? [closed]

I found a rock on a beach in north-east Evia, Greece. Half is light gray, and half is dark gray. There are white (or very light gray) thin lines that form swirls throughout, crossing the light/dark ...
14
votes
2answers
925 views

How to learn the different types of rock

I would like to be able to point to a piece of rock and say that is rock type such and such. I have tried learning but it literally seems like an endless list of types and sub types and the pictures ...
1
vote
2answers
738 views

Does grade of metamorphism apply to igneous and sedimentary rocks?

Does grade of metamorphism apply to igneous and sedimentary rocks? I know that grade of metamorphism applies to the scale in which a rock becomes crystallized. Or is it? Please also define grade of ...
3
votes
4answers
3k views

When metamorphic rocks undergo pressure, how are they changed?

When metamorphic rocks undergo pressure they are changed, but how are they changed? Do they become fragments of rocks? Doesn't that mean that the difference between sedimentary rocks and metamorphic ...
6
votes
0answers
170 views

Basalt vs. columnar basalt

I recently visited a cliff on the south coast of Ulva in the Inner Hebrides where there are ~10m thick flows of columnar basalt. The columnar basalt forming most of the cliff is sandwiched between ...
4
votes
2answers
2k views

What are the most common minerals at the Earth's surface?

I know how to find out the first few most common minerals, and I know how to find a list of 6800 minerals that one geologist found as a microscopic grain in this one meteorite. I can't seem to find a ...
3
votes
2answers
508 views

Was there once a glacier over Starcke national park in Queensland Australia?

I was randomly exploring Google Earth when I came across some sort of rock formation in northern Australia. The location of the rock formation with respect to Australia is shown below. It is in or ...
-2
votes
1answer
83 views

Color in Gems and Rocks [duplicate]

Why is it that gems/ rocks, such as Ruby, Sapphire, Topaz, etc... all have their own unique colors? Is this something that happens from chemical attraction with each stone upon formation?
1
vote
0answers
444 views

What does a negative value for the inclusive graphic standard deviation mean?

I'm calculating the inclusive graphic standard deviation for sediment from a cumulative frequency graph, with this formula: But when I plug in the numbers, I get a negative value, because my ranges ...
0
votes
1answer
600 views

The rock that gives birth to quartz sand

Thanks to one minute of the Earth we know that beach sand mother rock, besides the quartz itself, is (or was?) made of olivine, amphibole and orthoclase. I wonder, what is the name of that rock and ...
3
votes
0answers
131 views

How Common is Volcanic Tuff?

Volcanic tuff was a key material in the Roman invention of concrete, something that modern concrete, or "Portland cement", lacked. With tuff, not only would Roman concrete be waterproof, it would ...
1
vote
0answers
47 views

Weathering of silicates

I am trying to find a relationship between the silicate-rich rocks weathering products. For example I've found information regarding gabbro weathering in which, according the consulted source, in 100 ...
2
votes
1answer
182 views

Ions & elements, which is the correct terminology to use when discussing chemical compounds in Earth Science?

Different textbooks use different terminologies when discussing the same chemical compounds, for example when discussing the minerals... Elements / Compounds Sulfide minerals consist of metallic ...
0
votes
1answer
2k views

How long will it take for the ocean to erode Rockall?

Loosely related to the question Will the ocean eventually erode all land?: How long will it take for the ocean to erode Rockall (an uninhabited granite islet within the exclusive economic zone of the ...
0
votes
1answer
55 views

Is there any covalent crystals that can be easily synthesized?

I am looking for a kind of crystal that can be artificially made at relatively low temperatures (below 1500 degree Celsius) and relatively quickly (not geological time). The product is ideally ...
1
vote
1answer
256 views

Why do manganese nodules have different constitution than sea water?

Analysing the constituents of manganese nodules, we find that the relative proportion of minerals differs from that of the surrounding sea water. Can someone explain to me why the proportion of the ...
3
votes
0answers
49 views

Link between different ways of modeling permeability

The most famous equation describing the permeability $k$ of a soil is the Kozeny-Carman equation: $$k = \frac{\phi}{8}r^2 \approx \frac{\phi}{c}\left(\frac{V}{S}\right)^2$$ $\phi$: porosity V: pore ...