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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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1answer
80 views

Unknown semi-precious stone [closed]

On the handwork market I've found piece like this Merchant (who was reseller) didn't know its name. Have you any idea what is that? EDIT: I think it was about 5 on Moch's scale. It was black with ...
2
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2answers
107 views

Describing this rock [closed]

Is this rock granite? Can anyone help me identifying this rock and describing it?
2
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2answers
91 views

Need help to ID rock type [closed]

I found this rock in a freshly ploughed field, and it looked too unusual to pass up. Can anyone identify what it is?
2
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1answer
407 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 ...
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0answers
25 views

What would create the triangles in this rock I found in the Lehigh River [closed]

I collect rocks from the Lehigh Valley River, I have found some many interesting rock. With details that could not be from the water. Can you tell me what would cause the 3 triangle indents on this ...
2
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0answers
61 views

Is it an egg? What type of rock please? [closed]

This stone was found by my uncle in Western Queensland. It’s light brown in colour and smooth. It's very heavy for its size. 780 grams. Pocket knife doesn’t scratch it. many thanks.
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0answers
90 views

Identify rock found on beach in Florida [closed]

This rock was found in Florida on the beach on top of the sand. There were no others found. Color of rock is white, the outer rim is clear (see through) the inner layer is solid. The inner layer is ...
2
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1answer
76 views

What is this figurine made of: [closed]

Have several of these animal figurines, MADE IN USSR on bottom. Can't figure out what type of rock it is made from. Any ideas?
2
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0answers
67 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.
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2answers
2k views

What is the identity of this heavy, smooth, shiny black and red rock? [closed]

. It's very shiny and layered. It has rough texture but spots with smooth red colored pieces.
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0answers
640 views

What type of rock is this powdery white rock with a fairly smooth dark shell and rusty patches I found while digging up pipe? [closed]

This rock is sort of a dark grey/black and kind of shiny but more matte I'd say. It does have some brown rust-like spots on it. And the inside has little dimples in a what seems to be more chalky ...
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2answers
523 views

How are natural specimens, such as ‘Moqui Marbles’, distinguished from man-made artifacts?

If a particular type of rock specimen is found throughout Earth and is made entirely of natural minerals, but the individual specimens differ minutely from another in size and shape and look to be ...
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1answer
84 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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3answers
368 views

What is this lavender stone? [closed]

Can anyone identify this stone?
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2answers
87 views

Can someone help me to i identify this rock found in macedonia [closed]

Can someone help me identify this rock? Also, will it react to acid?
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4answers
542 views

What is this Lake Michigan rock? [closed]

Rock found along northern Lake Michigan, (Charlevoix, MI). Made up of very thin crystalline layers. There are small, round bubble like bumps that protrude from the surface. Doesn't show well in the ...
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2answers
59 views

Chloride ions for the salty seawater

Where does the chloride ions that are required for the salty taste of sea water come from ? I know that it is the weathering caused by the slightly acidic (due to dissolution of CO2 with water) rain ...
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1answer
93 views

Help me to identify this strange rock [closed]

About 9 years ago I found this rock in the middle of the river. It reminds me of a some kind of a volcanic rock, but I live in Finland, and we only have dead volcanoes around here. Outer layer is just ...
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1answer
820 views

What is this red rock with crystal white inside? [closed]

I found this rock in the desert. I found similar rocks that are crystal white on the inside, but this one is rough on the outside and all the others are smooth. Plus all the rough rocks doesn’t have a ...
1
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1answer
454 views

What is this stone or rock that looks like chocolate chip cookie dough? [closed]

Would anyone be able to tell me what kind of stone this is? It looks to have smoky quartz pieces throughout it but I’m not 100% sure. Has anyone seen something like this before? Thanks in advance!
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1answer
203 views

How can I tell the difference between granite and syenite?

(I'm not a geologist, just helping my kids collect rocks).
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1answer
125 views

What rock is this white stone with tendrils like an anemone? [closed]

Could someone please help me identify what this rock is and where it came from? Thank you!
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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.
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1answer
66 views

What is this rock found close to active volcano [closed]

Scratches glass Not affected by sandpaper on the bottom Depending on lighting, intense light, triangles everywhere Violet/light purple fluorescence
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1answer
27 views

Why don't pyroxenites and peridotites appear in Streckeisen's QAPF diagram?

Wikipedia says for QAPF diagrams: "A QAPF diagram is a double ternary diagram which is used to classify igneous rocks based on mineralogic composition." Why don't pyroxenites and peridotites ...
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2answers
117 views

Can anyone identify this stone [closed]

i found this stone on the east coast of south island in New Zealand, it's 200 grams and very hard,i used a metal file on it and it left steel residue on the stone.
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1answer
96 views

Glacial erratic - Granite or Gneiss? [closed]

This boulder is a glacial erratic in New Jersey. Can anyone tell if it's granite or gneiss? When you look at from the side, there appears to be foliation... but when you look at from the top or other ...
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1answer
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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2answers
853 views

Help identify this red and black rock [closed]

Last weekend in a field I found a rock that seems burned and heavier than other rocks, but I have no idea what it is. I measured body by using handmade tool afterwards calculated the density as 3.24&...
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1answer
93 views

What is this white and deep red rock found in Morocco? [closed]

Rock found in Morocco and haven't been able to figure out what it is! Please help!
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1answer
433 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 ...
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2answers
732 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 ...
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1answer
249 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 ...
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1answer
34 views

How to calculate or find the compressional stress wave velocity, Cp for a rock

In Cunningham's paper, "The Kuz-Ram fragmentation model - 20 years on", he makes mention of compressional stress wave velocity, Cp. He only comments that the Cp of granite = 5.2 km/s. I using a ...
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1answer
129 views

Need help identifying this rock [closed]

I need a little help identifying this rock. It was found somewhere in the Sahara Desert. It is very hard and leaves a beige streak on a steel file (might be the concretized dirt covering it). The ...
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1answer
57 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
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1answer
72 views

Help me identify this rock [closed]

Please help me identify type, region and name of this rock. Thank you
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1answer
71 views

What type of mineral is this? [closed]

My grandfather found this thing.
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0answers
57 views

How to identify this rock? [closed]

I am trying to identify this rock. I found it in Alberta. It is basalt? Jade? Or maybe it is extra-terrestrial?
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0answers
67 views

How can I find out if this is a geode without breaking it in half? [closed]

I found this rock today on my property. It looks similar to another rock I saw that was said to be a civil war cannon ball, however comments below suggest that it could be a geode. Are there any ...
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0answers
66 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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0answers
59 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 ...
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3answers
250 views

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

I apologize for any errors in my pictures or writing. My first post. [
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0answers
54 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 ...
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0answers
66 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 ...
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0answers
84 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:
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0answers
110 views

Can someone help me identify this crystal/stone? [closed]

I found this stone whilst on safari in Nairobi. Can anyone help me identify it please?
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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.
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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 ...
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0answers
132 views

Can you help me identify this rock? [closed]

We found this in our back yard (in Michigan) while digging one day. I'm curious about it, it seems different than others we've found. It's a pretty good size, about the size of a basketball.