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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3answers
859 views

If rocks are stones, what type of rock are gallstones? [closed]

From Wikipedia: Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a common rock, is a combination of the minerals quartz, ...
2
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1answer
166 views

What is this vesicular grey rock? [closed]

We found this rock in field, it is blue/dark blue and around it has 1 cm wide zone where it is like melted, it is 20 cm long, 1 7cm high and 15 cm long, it is almost a square shape, it was found in ...
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1answer
357 views

What is this stone? [closed]

My Uncle got this stone from Australia and he would like to know what it is exactly The paper is 210 mm on the long side. The stone feels like glass and is softer than metal. On the other side it ...
4
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1answer
653 views

What are these oblong shaped rocks called, with pigment inside? [closed]

There are these rocks we have -- not too common, usually find them in loads of small rocks, very seldom at random. They are perfectly oblong, and sort of smooth, but not quite as smooth as a river ...
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2answers
824 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.
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1answer
601 views

What are the blue spots in this rock? [closed]

The rock is 4 inches (~10 cm) long. The vendor claims this rock is from K2. Are the blue spots real or painted on?
4
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2answers
127 views

What are these crystals? [closed]

I have got a whole bunch of these crystals.
8
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2answers
620 views

Identification of dark red, metallic mineral [closed]

I recently found this mineral crystallised within quartz at a rock crushing plant. Because of this I have no idea where this rock came from as material is transported to the site from a variety of ...
4
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1answer
154 views

Can anyone tell me what this is? [closed]

I found this in Victorville, CA in a location known for finding black jade. It's a bluish color and a little translucent. I found some Amethyst on a hike a few weeks ago and that sparked a curiously ...
3
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1answer
88 views

What rock is this that I found on beach? [closed]

Found this on the beach in NY - it is a dark red colored rock with the green stones:
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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?
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1answer
98 views

Can you identify this rock with speckles and lines of colours.? [closed]

When the sunlight hits it, it shows up speckles and lines of colours. It could be from Malta.
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1answer
694 views

Could you please identify this rock for me [closed]

I found this rock several days ago and think it looks like RUBY ! Could you please help me to recognize it ?
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1answer
458 views

Are “monoliths” giant, isolated rocks sitting in dirt, or are they continuous with bedrock

I am at a loss for the precise, correct terminology, but I have read in Wikipedia that Uluru is not a monolith, but Savandurga is, and that I probably shouldn't be using the word monolith to begin ...
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1answer
70 views

Please identify markings [closed]

these are the other rocks I found near Lake Ontario
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1answer
324 views

What are the circular features in this rock? [closed]

I found this rock by the shore of Lake Ontario. It's light weight and it was grouped with some other rocks with the same patterns.
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2answers
126 views

Can anyone help me identify this? [closed]

Was gifted this . Just want to know what it is called ?
2
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1answer
344 views

Please help me identify this very cool rock with a face [closed]

I found this rock where there was a lot of petrified wood but this does not resemble any of the many pieces of petrified wood that I have collected. It has the shape of a face, in my opinion. It has ...
5
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1answer
375 views

I'm trying to find the name of this rock [closed]

I found it upstate New York... Can someone please help me identify this rock. I added photos with different lighting. It's a very dark purple with a mix color showing more in the center. Its very soft ...
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2answers
468 views

Looking for rock identification [closed]

This is another rock I found on my first search in Easton, PA. I am just starting out and looking to gain knowledge, even on basic rocks and minerals. Can you help me identify this?
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1answer
170 views

Seeking rock identification [closed]

This rock was found it Easton, Pennsylvania by the Delaware River. I'm just starting to become interested and collecting and hoping to use this site to gain knowledge on the rocks and minerals I find! ...
4
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2answers
447 views

Can someone identify this rock with fibrous white veins [closed]

What is this I found this in my back yard im unsure as to what it is and would really like to know.
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2answers
702 views

Is this iron ore? If so what kind? And is it naturally deposited in texhoma? [closed]

It's completely hollow on the inside and looks like a bubble while layered on the outside. Slightly rusted.
8
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1answer
843 views

Rock ID: brittle black/white w/ crystals & mica-like cleavage layers, Raleigh, NC, USA [closed]

Where it was Found: I found the rock laying on the sidewalk near some landscaping at my apartment complex in Raleigh, NC. Size: The largest intact portion of the rock is about 2.2 cm in diameter. ...
4
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1answer
400 views

What rock is this? [closed]

I've had this little guy for a while now and have been trying to identify it for some time with no luck. It looks like its oxidized with tiny little crystals, but it's hard to tell for sure. Any ...
8
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2answers
15k views

How long does it take for a stone to decompose?

We see stones and they appear to be the same throughout our life time. Mountains also appear to not significantly change. So do mountains and stones decompose? What is the life span of a stone? After ...
4
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2answers
187 views

Help me to identify this rock, please, [closed]

Can anyone tell me what this rock is? It was found on the rocky beach at 'Glen Boreraig' on the Isle of Skye, Scottland. Definitely water-worn. It is 9.5 cm x 4.5 cm with inner darker part 4.5 cm x ...
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2answers
308 views

what is this white rock, Saudi Arabia mountains [closed]

Hello, my friend has this solid white rock, can you tell me about it, thanks all.
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2answers
725 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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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 ...
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3answers
3k views

Can someone please help identify my rock [closed]

Can somebody please help. I found this rock on the beach in the south of England. It seems to have a number of small shards of what look like crystal or glass spread around it whilst the rock itself ...
3
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1answer
397 views

Identification of mineral [closed]

I recently visited a quarry site and brought home a rock sample that had two clusters of cubic crystals on its surface. I am unsure what the mineral is, I think it may be fluorite but I am not certain....
4
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1answer
382 views

Any idea what are these circular rock marks?

During a family trip in the Israeli National Trail in the Pora Stream part (31.496871, 34.770928), I noticed these circular rock marks. Any idea what are they?
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2answers
414 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 ...
4
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1answer
216 views

Fossils in this rock from Montana? [closed]

I found this in SE montana. It feels quite dense and is about 1.5". The lighter colored divets cover the entire thing and some have holes going deeper into the stone. I was told it could possibly be ...
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2answers
3k views

Rock ID: smooth, black, durable rock from Lake Ontario [closed]

What is this black rock? I found it beneath the waters of Lake Ontario near the shoreline, it is a dark greyish-black with small flecks of mineral deposits on it that are visible in the light. The ...
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1answer
79 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?
4
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1answer
164 views

Is this a rock? [closed]

My son found this in our front yard. We live in Richardson, TX. It is brittle and little gold flecks fall from it when you handle it. The darker smooth parts are like a mirror. The clear part at the ...
4
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3answers
202 views

What is the mineral showing in this piece of gneiss? [closed]

I was wondering what kind of mineral I'm seeing in this piece of gneiss (at least I think it's gneiss). The largest are 1 cm across. I found it in the Austrian Alps (Silvretta). I thought it could be ...
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2answers
99 views

Rock ID, Hard, From Anti-Atlas mountains [closed]

I have been on a hiking trip lately (trying to find some potential fossil sites) and i have collected some rocks, i would like you to help me identify them. Rock 1: (i think it's limestone) Rock 2: ...
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1answer
201 views

Can someone help me identify what this is and its worth? [closed]

Its mostly dark brown, but can barely identify this specific stone. Can anyone help?
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1answer
143 views

Can anyone identify this stone? [closed]

I found this rock at the weekend in the forest of Haigh Hall, Standish. It seems to be a solid mass of fibrous material. I have given it a scrub with warm water and a toothbrush just to get rid of ...
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1answer
519 views

Help…would like to find out what kind of rock this is. [closed]

Not too sure what kind of rock this is, very interesting looking. Anyone have an ideas. Was found north of the badlands, South of Rapid City.
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1answer
582 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 ...
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1answer
154 views

Rock ID: Bone and potato-shaped, copper-colored [closed]

I found these two intriguing rocks on the UK's seaside. They have an unusual potato shape and copper/green color. Whrn knocked against each other, the sound is clear, metallic and the vibrations keep ...
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3answers
1k views

How was this egg shaped rock made and what is it? [closed]

The following small egg-like rock was found laying on the ground in Tampere, a city in southern Finland. It weights about 950 grams, has a volume of about 360 cm3 and thus a density of about 2600 kg/...
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0answers
129 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.
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0answers
115 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 ...
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0answers
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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 ...
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1answer
165 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 ...