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".

21 questions with no upvoted or accepted answers
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8
votes
1answer
257 views

What is the global distribution of oil filled geodes?

In a general 40 mile radius of Keokuk, Iowa many sedimentary geodes can be found. They are abundant in the Warsaw Formation with the type section at Geode Glenn in Warsaw, Illinois. In one specific ...
6
votes
0answers
160 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
1answer
114 views

Can anyone help me identify this rock found in Tulsa Oklahoma?

I was working in my front yard in Tulsa Oklahoma and ran over this rock with my lawnmower. It was logged in the ground enough I didn’t see it. It’s 2.5 inches in length. Black in color with what ...
4
votes
1answer
169 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. ...
4
votes
0answers
523 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 ...
3
votes
0answers
59 views

What is in this rock?

There were many, many examples of this, my photo simply shows a situation where I had even light and time to take a photo without making anyone wait for me. The basic rock is obviously sandstone. ...
3
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0answers
74 views

What is this 6in Nor Cal beach boulder with waxy veins?

Nor Cal beach @ low tide. 6in, photographed wet, post acid wash. Veins look waxy.
3
votes
0answers
286 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 ...
3
votes
0answers
111 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 ...
3
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0answers
47 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 ...
2
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0answers
134 views

Rock ID: black, white and orange, from Malaga, Spain

I picked up some very interesting rocks and pebbles on the beach in Malaga, Spain this summer. They are predominately flat and colored dark grey crisscrossed with stripes of orange and white. The dark ...
2
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0answers
66 views

Whats this stone?

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.
1
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0answers
51 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 ...
1
vote
0answers
64 views

Rock / Fossil ID?

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 ...
1
vote
0answers
74 views

I was wondering if anyone could help me identify this rock

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.
1
vote
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 ...
1
vote
0answers
46 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 ...
1
vote
0answers
369 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
3answers
81 views

What kind of red rock is this?

I don’t know much about were I live, I am from ny and only moved here a few years ago. I found it in Smithfield nc we’re I love with my dad and kids now.. I wish I had more information. Yes the rock ...
0
votes
1answer
128 views

Please identify this rock

I found this rock along the Illinois river basin in cave junction, oregon. It was laying on the top layer of a massive beach of rock. It's shape is what drew me too it, then after closer inspection ...
0
votes
1answer
82 views

Help identify my redbrown rock with crystal like formation on the inside

This rock is red/orange/brown in color. It is slightly clear/translucent when held up to light. Will not scratch with a knife. Has a crystal like structure on the inside.