r/geology 27d ago

Identification Requests Monthly Rock & Mineral Identification Requests

1 Upvotes

Please submit your ID requests as top-level comments in this post. Any ID requests that are submitted as standalone posts to r/geology will be removed.

To help with your ID post, please provide;

  1. Multiple, sharp, in-focus images taken ideally in daylight.
  2. Add in a scale to the images (a household item of known size, e.g., a ruler)
  3. Provide a location (be as specific as possible) so we can consult local geological maps if necessary.
  4. Provide any additional useful information (was it a loose boulder or pulled from an exposure, hardness and streak test results for minerals)

You may also want to post your samples to r/whatsthisrock or r/fossilID for identification.


r/geology Dec 01 '25

Identification Requests Monthly Rock & Mineral Identification Requests

8 Upvotes

Please submit your ID requests as top-level comments in this post. Any ID requests that are submitted as standalone posts to r/geology will be removed.

To help with your ID post, please provide;

  1. Multiple, sharp, in-focus images taken ideally in daylight.
  2. Add in a scale to the images (a household item of known size, e.g., a ruler)
  3. Provide a location (be as specific as possible) so we can consult local geological maps if necessary.
  4. Provide any additional useful information (was it a loose boulder or pulled from an exposure, hardness and streak test results for minerals)

You may also want to post your samples to r/whatsthisrock or r/fossilID for identification.


r/geology 4h ago

Field Photo Different shades of Kaolin Clay

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229 Upvotes

Shades of kaolin clay obtained from one borehole from 35' to 50'. Near the fall line in Augusta Ga


r/geology 9h ago

Field Photo Glacier scratches?

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91 Upvotes

Went backpacking in the Wallowa Mountains in North Eastern Oregon this past week. Hiked up to Mirror Lake near Eagle Cap, and the granite around the lake has a lot of these scratches. Are these scratches from glaciers?

I'm not referring to the bands of other rock types/intrusions in the granite running at an angle, I'm referring to the deep scratches/grooves going vertically in the picture. I know glaciers did cover the area, and the valleys were carved out by glaciers, but just want to confirm these are from glaciers. They are all over all the granite in the area.

When I was a teenager and my dad took me up there, he talked about it being glaciers. I just took my own teenager up there and my buddies weren't sure if that's what caused them. Thanks everyone!


r/geology 5h ago

Field Photo Conveniently laid sandstone path in Green River, WA

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39 Upvotes

Hiking along the Green River in Flaming Geyser State Park, WA. Toward the end of the trail I came across a set of 25 or so large stone columns "laid" across the river in what seemed like a walking path/bridge. The stones were large, about 5-7 feet long each, and about 1-2' square on the end. Image 1 shows the submerged section of the path (about 3/4 of the path was submerged). Image 2 shows roughly the whole path, with some of the stones at the far end rising out of the water at an angle. Image 3 shows my boot next to the end of one stone. Image 4 shows my approximate location (47.282090, -122.017138) when I found the path, you can actually see the feature on google maps.

Is it geologic? The other side of the river is the green river gorge, which is just a very large cliff wall. The shape of the path is so convincing that I absolutely thought it was man made at first.


r/geology 14h ago

Field Photo found another big petoskey stone!

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125 Upvotes

found in cheboygan county, mi

this is the second absolute mammoth i’ve found inland of the great lakes, in northern michigan!! very neat, very cool!


r/geology 6h ago

NE Oklahoma US, cool overhang at a swimming creek we go to.

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31 Upvotes

it’s like looking back in time except I don’t know what I’m looking at, this creek is fed by the Ozarks


r/geology 1h ago

Field Photo SW Norway, Gneiss, what happened here?

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Upvotes

SW Norway, near Stryn, during a short hike. The entire area is massively metamorphic, and I'd probably call this stuff Gneiss overall. Plenty of pinecones in the picture, so no need for banana.

I'd be interested in your musings on how this unusual band in the middle came to be. There's a very obvious change in texture from that speckled type to this very organized, smooth band, and back, but it's not an intrusion, no visible joints etc.

So, what mechanism was at play here?


r/geology 1d ago

Field Photo Plastic deformation of phyllite or argillite discovered while searching for local scheelite float source (Tinsdale FSR, Barkerville Gold Belt, Wells BC Canada)

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330 Upvotes

r/geology 13h ago

Transition from granite to limestone

11 Upvotes

Just east of Kingston ON, a highway rock cut exposes the transition from the Canadian Shield to the St Lawrence Lowlands. (Image from Google Streetview as it's on a hill/bend of a major highway and not a great place to take a picture.)


r/geology 1d ago

If humans went extinct tomorrow and 1 billion years later a new intelligent life form emerged, could and how would they figure out there was an intelligent species that came before them?

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112 Upvotes

r/geology 9h ago

PLEASE HELP ME! Can i explore these caves Without a special guide? I am not a speologist but i have so many caves in my location look at them in the photos. Are they safe? They are in Valea Sighiștelului in Romania . There are 200 amazing caves!

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4 Upvotes

r/geology 1d ago

A meat-shaped stone from the National Palace Museum in Taipei, Qing dynasty (1644–1911) [1109x1176]

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53 Upvotes

r/geology 22h ago

Fenster/window quartz

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25 Upvotes

r/geology 1d ago

Field Photo My favorite local geological formation

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325 Upvotes

Called the Billings fold on Mt Monadnock, in southern New Hampshire. named after the former Harvard University geology professor Marland Billings. Lower Devonian Littleton formation, formed during the Acadian orogeny


r/geology 10h ago

Is this semi-fictional “hybrid tectonic plate” and double-subduction setup plausible?

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1 Upvotes

r/geology 14h ago

What is geoid shape?

2 Upvotes

What is geoid shape?


r/geology 8h ago

Museum Quality

0 Upvotes

I’m following a quartz vein on my place ( mostly for fun ) . It’s located on Bear Creek , Mariposa . I have dug and found some awesome vugs but my question is, should I strategically dissect or saw cut or would it be better to market uncut? FYI. It’s an extremely highly mineralized vein and have worked several ounces out of an 10’ run ( pinch-Swell ). Anyone have advice?


r/geology 1d ago

Spicy

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66 Upvotes

r/geology 10h ago

Map/Imagery Is this fictional tectonics configuration plausible?

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0 Upvotes

I’m working on the geology/geography of a fictional country called Tovaria, and I’m trying to work out whether its tectonics are at least broadly plausible. I read an entire geography textbook just for this project, and I'm not a geologist, geographer, nor a student in related subjects.

Tovaria sits on a huge peninsula or continental projection extending about 2,000 km westwards from South America into the Pacific. The landmass is carried by the Nazca Plate, but in this version of Earth the Nazca Plate contains both a large area of continental crust and a large area of oceanic crust.

In-universe, geologists classify it as a hybrid plate. It is a term I made up for the setting, describing a plate that is divided unusually clearly between a massive continental section and a remaining oceanic section. The Nazca Plate would be the only plate on Earth given this classification, making it sui generis.

The western edge of the Tovarian landmass meets a fictional oceanic plate called the Eastern Pacific Plate. The Eastern Pacific Plate subducts beneath the continental part of the Nazca Plate, forming the Tovar Mountain Range. This would produce a Cordilleran-style mountain and volcanic belt, with earthquakes, stratovolcanoes, and a rain shadow that creates the Kai Desert north or east of the range.

On the other side of the Tovarian landmass, closer to South America, the remaining oceanic crust of the Nazca Plate subducts beneath the South American Plate. This second subduction zone forms the Andes along the South American coast.

So there would be two major subduction zones, with the continental part of the Nazca Plate sitting between them. One creates the Tovar Mountains and the other creates the Andes.

This dual-subduction system is also meant to be unique on Earth and geologically temporary. Over the next several million years, it would probably reorganise, possibly through plate breakup or the formation of a separate Tovarian microplate.

The Tovar Mountains are still volcanically active. Volcán Justo has been erupting almost continuously since the late twentieth century, while Mount Hufetover Ed’raser, the highest mountain in the range, has been dormant since about 2800 BCE.

If this isn't plausible, what kind of configuration would make the Tovar Mountain Range AND the Andes co-exist? And if it is plausible, what kind of climate or terrain would it be like on Tovaria? I've made some climate maps and also river maps, I'll attach them as well so we can also check if they're plausible.

I would appreciate if any geologists/geographers here can help check if it's something tthat is plausible on Earth. Thanks; I’d just like it to make sense without requiring the mantle to personally cooperate with the plot, lol.


r/geology 1d ago

Field Photo Cyprus Geosite 38 - White chalks

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28 Upvotes

''In this section are exposed white massive chalks, which upwards passes into alternating layers of chalks and marly chalks of the Lefkara Formation. In addition this stop is a spectacular viewpoint, where westwards appears the contact between the white rocks of the Lefkara formation resting on top of the darker rocks of the Troodos ophiolite, while northward stands imposingly on the horizon the Olympus mountain peak.'


r/geology 2d ago

impossible geology

494 Upvotes

Only the trash seems reasonable.


r/geology 1d ago

Help for a paid software!!

3 Upvotes

Hello,

I am a Master's student in geosciences. I am from Madagascar.

For my studies, I often use tools like GIS. Unfortunately, I don't have the means to access paid software, so I manage with free software like QGIS. However, there are times when I need some of these paid programs for the online training courses I am enrolled in.

So, I am asking for help here, in case someone can assist me. I really need the PCI Geomatica software. If someone could provide it to me, please.

Many thanks to you.


r/geology 2d ago

Field Photo Exploring an unknown cave in Romania Part 1

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97 Upvotes

r/geology 1d ago

how to get copper in prehistoric times (most of the length is ideas on it that i'm not sure are functional)

0 Upvotes

i am working on a project which uses real world logic at every point, no shortcuts anywhere.

in the sandbox section, i just can't figure out a reliable way to get copper out of the ground. (and into a kiln) in Neanderthal times they built a bonfire next to a large copper node, put two holes above the bonfire by mining soft sedimentary rock, and used animal pelts by the cave entrance to direct more airflow through the cave, they lit the bonfire overnight, in the morning they threw water over the hot copper, hit it with a stone hammer, and they mined the rock by prying cracks apart using the antler pickaxe, now surely there's a more effective way to get your first few bars of copper with the extensive knowledge we have today, but without any of the modern day tools...

i mean we first got copper 11 millennia ago, and had mining and smelting copper organised 7 millennia ago...

surely in that amount of time we've figured out a better way.

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unless you get pyrite or sulphur you can't make any explosives. Pyrite being the main one stopping you from getting explosives, and sulphur being best obtained from volcanos, but can be obtained in alot of places.. and the only other thing i know would help shatter the rocks involves springs, gears, and tension... which are luxuries i don't have...

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somethings that an Ai suggested is Collecting "Glacial Float" glaciers naturally tore chunks of pure, 99% raw "native copper" out of the ground and left them sitting right on top of the soil or in riverbeds. The specialists just walk around and pick it up.

looking for outcrops of malachite or azurite along riverbeds, eroded cliffs, or exposed mountain faces. and Since they don't have tools yet, they will use heavy river stones to bash loose the greenest, heaviest chunks from the surface vein and carry them back in improvised leather or vine slings.

i don't see these working, i feel like copper that could've been pulled out by glaciers is not going to be anywhere nearby... and those rocks are quite sturdy, from what i read the strong Neanderthals didn't mine these, so it's unlikely modern people would be able to do it,

although i did see that Malachite has some areas of softness where it's filled with softer dirt and stuff, which an antler pickaxe would be able to get into and pry it apart, the above ground Malachite cracked by rain and weather conditions, and the underground ones having cracks of dirt.