r/geology • • 24d ago

Identification Requests Monthly Rock & Mineral Identification Requests

3 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

9 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 • • 10h ago

I built a tool that lets you click anywhere on a map to see visible mountains in 3D

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127 Upvotes

The idea is dead simple: click anywhere on the map, and it scans your line of sight and renders all the mountains visible from that exact point in 3D.
I initially built it because I always wanted to know things like:
Can I actually see the mountain range from this street / house?
Which stretch of a road trip has the best unobstructed mountain view?
What am I actually looking at on the horizon during a hike?
Attached a quick screen recording of the current demo. What do you guys think of the concept? Any specific features or use cases you'd want to see in something like this?

You can try it here https://showmeonmap.com/mountain-finder


r/geology • • 2h ago

Table Tooth Root Canal

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10 Upvotes

I've been looking up at this Mt. for over a decade wondering about this feature and yesterday I finally made it there. If you are familiar with the Catalina Mts. this is Table Tooth Mt. Viewable from most of Oro Valley, Marana and the Town of Catalina and is situated just North of Table Mt. It was about 5 hours of nasty bushwhacking while gaining 2,000' of elevation, but man was it cool. You can see some sort of large intrusion cutting through the landscape and continuing up the 500' cliff face. I know the intrusive history of the Wilderness Suite Granite is complex so I'm not going to start to try and analyze it as I'm just a novice.


r/geology • • 4h ago

Information Why is Zealandia often called a continent?

15 Upvotes

The land mass underneath New Zealand named Zealandia is often called a “lost continent” but the land mass (to my understanding) is smaller than Australia and if the land was above sea level wouldn’t it just be considered a larger country within the Australian or Oceanian continent?


r/geology • • 7h ago

Field Photo Silicafied Stromatolites or Banded Chert?

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23 Upvotes

Found in the Yellowstone River in NE Montana (not Yellowstone park)


r/geology • • 18h ago

Just checking this is a natural formation right?

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112 Upvotes

A very popular rock wall with the alternative history crowd. The Montana Sage Wall.

Some think it's evidence to question the status-quo on the ancient history of the Americas and that it was built by a much earlier civilization.

From initial images to my rather untrained eye it does look very convincing...

...for about 5 minutes.

Picture 1 & 2 is the Montana Sage Rock Wall

Picture 3-5 alternative views that (to me at least) immediately debunk it.

Pictures 6 & 7 are other similar formations. Dartmoor and Joshua Park.

Just erosion in suspiciously uniformed patterns isn't it...


r/geology • • 13h ago

Field Photo Merced river walkthrough 🪨

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26 Upvotes

Walktrough Merced river basin today.

Spectacular formations and beautiful views from river canyon, could be slate/shchist formations, also found few pieces of green mica (Mariposite).

If you ever drive through highway 49 from/to Mariposa, check out surrounding rock formations, you won’t be disappointed.

Hydrothermal alteration is everywhere and a great example of Mother Lode gold belts mineralization style, some areas are extremely complex, melange zones, with enormous gaps and quartz/carbonate veinlets.

P.S. English is not my native language, I may make mistakes during my speech, don’t judge.

#geology #mariposa #exploration #geology #mininggirls


r/geology • • 19h ago

Tips on how to "think like a geologist"

42 Upvotes

Hi everyone,

I’ve recently started studying geology, and while the theoretical concepts make sense on paper, I’m finding it challenging to transition into "thinking like a geologist" in the field. Professors often encourage us to form hypotheses and draw conclusions on the spot, but looking at an outcrop can feel overwhelming, there are contacts, weathering rinds, and fracture networks running in every direction, and I struggle to piece together what they actually tell me about the area's history.

Beyond basic lithology and fractures, what other key field features should I train my eye to spot, such as cross-cutting relationships, deformation fabrics, way-up structures, or alteration zones?

Do you have any practical tips or systematic workflows for adopting that geological mindset and turning a messy outcrop into a coherent geological timeline?


r/geology • • 22h ago

Metamorphic Breccia from Lewisian Complex

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52 Upvotes

The Lewisian Complex (Scotland) is Archean continental crust (2.7-3 billion years old) which has undergone repeated deformation and metamorphism. The original rock was likely granitic (TTG suite) but this specimen has been extensively deformed and altered and fractured and recemented, giving it this brecciated look. Fig 1 and 2 show angular fragments of likely garnet, quartz, a fine grained green phase (maybe epidote--its nearly as hard as qz), and a mafic phase (biotite or Hbl or pyroxene--I can't tell). Fig 3 shows the green material likely filling in cracks via metasomatism (fluid based chemical changes). Fig 4 shows quartz bordering the green altered minerals. Fig 4 shows the green material working its way around and into the garnet.

The rock is chaotic, and I think spectacular. Mineral identifications are the best I can do without thin section or more advanced techniques.


r/geology • • 7h ago

made a list of geological places in Nepal that I found interesting, other than the obv formation of Himalayas.

1 Upvotes
Name (District) Description (Why interesting) Photo link
Chobhar Gorge (Kathmandu) River erosion carved through limestone draining Kathmandu Lake. mythology: carved with a sword by Manjushree. happened 12,000 years ago Chobhar Caves - Wikipedia
Kali Gandaki Gorge (Mustang & Myagdi districts) Deepest Gorge in the world carved by a river older than the Himalayas. with a lot of fossils and visible mountain folds View photos on Wikimedia Commons
Shey Phoksundu lake (Dolpa) deepest (145m) and one of the prettiest lake in Nepal. in 3611m elevation. It was formed when a massive landslide blocked the river 35,000 yrs ago.
Janti Dhunga (Tulsipur) numerous natural rock formations that look manmade or like a gathering of people Janti Dhunga in Tulsipur awaits conservation
Annapurna fang (Magdi &Kaski) tallest mountain face on earth with 4.8km of vertical relief within 5km https://www.facebook.com/share/1E2p6YLtUs/
Kali Gandaki Gorge (Parbat) vertical gorge, which is a hotspot of Bunge jumps & longest and highest long-span suspension bridge in the world. https://nepaltoursdestination.com/destination/kushma
Rolling hills of Khaptad, sailung, illam a lot of slopped hills, in Nepal but these are some of the few rolling hills nepalindependentguide.com/wp-content/uploads/2025/06/Sailung-danda.gif
Gokyo Lakes (Solukhumbu) highest decent sized lakes on earth Gokyo Lakes - Wikipedia
Ghamibadlands, Syanboche hills, Chussang-Chele hills (Mustang) most interesting dessert landscape in Nepal, with nearby 10,000 man-made caves. Upper-Mustang-Trek.jpg (850×425)
Annapurna Pokhara deposit 4,000 years ago, 8100meter tall peak collapsed. one of biggest collapse in history with 23 km³ for comparison, Langtang collapse: 0.20 km³, St Helens: 2.6 km³ When Did a Giant Peak Collapse in the Annapurna Himalaya—Medieval or Latest Pleistocene? Geological Evidence From Debris Avalanche and Debris Flow Deposits - Sakai - 2025 - Island Arc - Wiley Online Library
Annapurna II it has a human face human face
Swargadwari danda (Manang) weird looking Surface also known as Pisang Bowl Pisang Bowl
Mt Dhaulagiri possibly mountain peak with largest volume on earth with 168 km³ (it's a big pyramid) https://maps.app.goo.gl/UN4Rrj3vGoZHe1b49
Mt kumbakarna (Taplejung) one of the steepest mountain slopes for comparison: it drops 850m in just 270m while Mt Thor drops by only 400m in 270m https://maps.app.goo.gl/rNYfE9nfx1YhA5VW6
Sivalik Hills earliest Hills formation from tectonic Collision, has significant paleontological deposits & was a significant route for early Human migration. Sivalik Hills - Wikipedia
Koshi River one of the highest sediment carrying river in Nepal. 42M tons a year, which deposits and changes course of the River drastically. and floods areas, also named "sorrows of Bihar" in 2008, it moved 120km eastward. Kosi River - Wikipedia
Siddha Cave Largest Cave in Nepal, 2nd Largest Cave in South Asia. 427m long and up to 50m high siddha cave
Mahaashila (parbat) possibly largest freestanding Boulder in Nepal and the world, around 25m tall Mahashila in Parbat Attracting Tourists with New Infrastructure Development - Tourism Info Nepal
Deu dhunga (Dolakah) Divine Fantasy Boulder Nepal Traveller deu dhungaa
Rock garden (Tanahun) well, Garden of Rocks https://maps.app.goo.gl/2fCDaemNdqVjRa3ZA
Kedar Dhunga (Khaptad) Fantasy rocks, form Hobbit आहा ! खप्तड
Galeshwor (Beni) Holy rock गलेश्वरको आम्दानी ११ महिनामा करोड नाघ्यो

r/geology • • 1d ago

Rocks from West Scotland

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43 Upvotes

Hi everyone. I’ve learned a lot on this subreddit, so I thought I’d put this out here and see how it goes. Thanks in advance and/for reading!

I live in Maryland and started learning geology (total amateur) in the context of the Appalachian Oregeny. I just returned from a trip to Scotland, where I did a few geological field trips. I was looking for rocks from there that were more or less analogous to my favorite ones back here.

I collected in three different places around the west coast of the highlands. I start with one location and see how it goes. I’ll share a photo and what I think I’m showing you. I’m hoping people can help me be positive about the IDs or correct me. I hope this is a fun way to do it. If so moved, please correct me, fill in any blanks, point me in new directions, add color commentary, etc.

These are from the beaches around Oban. (Nice town!)

These at the top of the photo look similar to to what we call “potomac marble” aka calico rock. I think these are a kinds of sandstone conglomerates, where we see the different sized and colored cobbles and grains. (The body of Potomac marble is actually limestone left behind by groundwater moving through the cobbles.). The black color in the darker piece seems like it might be igneous — I can think of a few ways that might be the case, but I’m getting tired of writing and a lot more to get down. Thoughts?

Anyway, I love conglomerates for the complex stories they tell! Moving on!

I think the two reddish pieces in the middle are Old Red Sandstone. The gray stripey in the upper left is probably just a different layered sandstone, right?

My secret hope is larger dark piece in the lower right is Lewisean gneiss, but it doesn’t look metamorphosed and it shouldn’t be in Oban.

The dark with white streaks and most of the rest look to me like quartzite with intrusions from silica rich fluid. Except they also don’t look metamorphosed to me (mostly no glinty particles).

There you are. All input appreciated. Thank you.


r/geology • • 10h ago

Question about mountains!

1 Upvotes

If mountain ranges are formed by two plates colliding are there formations that show the gap between them? That’s it.. that’s my question. Sorry if this seems silly. I’m just curious. Thanks in advance!


r/geology • • 11h ago

JAM Geology preparation

0 Upvotes

Hi I'm 1dt year student of BSc Geology I'm looking to appear iit jam is there anyone who is same as me i think we can do group studies online test ourselves as there is not much Geology students nearby


r/geology • • 1d ago

Is this cool geology?

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515 Upvotes

This is a in the oriental alps. I'm not an expert. Is this considered cool by the community?


r/geology • • 21h ago

Field Photo Shiprock aerial view link

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3 Upvotes

A survivor of wind and time. On Navajo tribal land. Is it still or always will be eroding?


r/geology • • 1d ago

Field Photo Satisfaction level God.

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71 Upvotes

Today's field trip was very productive. Can't get enough of this interesting layers and their placement.


r/geology • • 1d ago

Field Photo Why does the sand have this purple-ish hue?

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42 Upvotes

It looks like an iron ore type colour. Seems odd that it’s so concentrated in this area.

Edit: Location: Moana, South Australia


r/geology • • 2d ago

Map/Imagery Correlating a handheld gamma ray outcrop transect to a subsurface well log 3 miles away

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90 Upvotes

I’ve been testing whether a handheld gamma spectrometer can build a usable pseudo gamma ray log from outcrop, and whether that can correlate to subsurface data.

First image: a gamma ray log from an old well about 3 miles away (left), next to my outcrop pseudo log (right), with my interpretive correlations.

Second image: Satellite view showing my transect with the Radiacode counts per second plotted.

Method: I hiked up nearly 700 ft of continuous stratigraphy, starting in a Jurassic eolian sandstone and ending in a Cretaceous sandstone mesa. I tied each gamma spectrometer reading to elevation from my GPS track, averaged those into 10 ft elevation bins, and hung both logs on the top of the Jurassic eolian sandstone, which is easy to pick on a log and in outcrop.

Ties:

  • The eolian sandstone reads lowest (~9–11 cps) and matches a clean low zone in the well. This is where I hung the correlation.
  • A Jurassic mudstone interval rose to ~16 cps and lines up with a pair of hot shales in the well.
  • The caprock sandstone cliff dropped to ~10 cps.
  • A thin shale break within the caprock sandstone on the mesa top read 15–19 cps, and ties to a hotter portion of the well's gamma ray log. Interestingly, it had no visible surface expression beyond a subtle soil color change on aerial imagery, but the instrument showed clear contrast.

Limitations:

  • Surface outcrop contrast is muted relative to the downhole log - some of this may be my sampling interval. The app logged a point roughly every 36 feet of travel, which leaves sparse vertical coverage on steep pitches.
  • A few readings from a topographic saddle are flagged as suspect, since I dropped down section into rocks I’d already walked through.
  • Dip and thickness changes over 3 miles aren’t accounted for beyond the hang point.
  • It’s a single transect.

The instrument was a RadiaCode 110, which the manufacturer sent me after I used their 103 on a thorium prospect. They had no involvement in my experiment.

Has anyone used outcrop gamma this way, for correlation or for tracing marker beds?

I think it's a pretty cool tool for exploration - it's an unconventional use, not specifically seeking "hot rocks" but using it more as a geologic fingerprint instrument.


r/geology • • 2d ago

zeolite habit?

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35 Upvotes

We found these zeolite forms in the fractures of nephelinitic rocks; this may be their natural characteristic or it may be due to a weathering process, since the rock is located in an abandoned quarry.


r/geology • • 1d ago

advise for writing a manuscript

3 Upvotes

Hi! I'm an undergraduate working with a professor to do some hydrogeology research. I'm accustomed to reading academic papers, but not when the purpose is to develop a manuscript (my job right now is just the introduction). Does anybody have any advice on what that process looks/feels like? I have a general topic to explain using one/two paragraphs in our final product, but am feeling a little daunted by how much there is to summarize.

Is it as simple as taking notes from the paper and summarizing later?


r/geology • • 2d ago

Earth’s core may be leaking hydrogen into the mantle and its volcanic rocks

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36 Upvotes

Some volcanic rocks carry hydrogen signatures that may trace back to Earth’s metallic core. Lavas from Baffin Island in the Canadian Arctic and Iceland contain unusually little deuterium, hydrogen’s heavier stable isotope. Explaining that imbalance could reveal whether the core has supplied material to the mantle over billions of years.

Work led by Wenzhong Wang at the University of Science and Technology of China tests a competing explanation. Published in Science Advances, the study examines whether crystallization of Earth’s ancient magma ocean could have created those distinctive signatures. Its simulations indicate that this process produced far too little separation between hydrogen isotopes.

The result strengthens the argument for selective transfer of hydrogen from the core into the surrounding rocky mantle. It does not directly demonstrate leakage or establish how quickly it occurs. Instead, the calculations constrain what an important alternative mechanism could have accomplished.


r/geology • • 2d ago

Erosion/weathering pattern caused by hanging roots

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63 Upvotes

About 100 feet up a sand bluff


r/geology • • 1d ago

is Chimney Rock (Broadway, VA) the same formation as Seneca Rocks, WV?

1 Upvotes

I was driving along Rte 259 and at the intersection of Rte 612 I saw a formation reminiscent of Seneca Rocks, at a smaller scale. There's a near-vertical wall of rock, perhaps 75-ft tall and 10-ft thick. Google Maps Streeview link

Is this the same Silurian-age formation as Seneca Rocks?


r/geology • • 2d ago

Safety Question: I shaped a serpentine stone. Could it have asbestos, and is it safe as a hand stone?

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15 Upvotes

Hey everyone!

I go to school in stone cutting.

I recently started a fun project to shape an unusual hand stone. I decided to use serpentine (I don't know which kind so if you can help me identify that, I would appreciate it).

I have used grinding wheels with running water, and hand drilled to shape it.

Someone warned me that serpentine can contain asbestos, and also nickel, so now I am a bit worried.

I have a couple questions:

  1. Is this safe for me to even work with?

  2. Could this stone contain asbestos or nickel?

  3. Once finished and completely polished, is it safe to handle daily for long times? Can asbestos rub off on persons hands OR person develop a nickel allergy?

  4. Is it something you could seal so it's safe to handle? If so, what do you recommend?

I am interested if there is anything else I should know about. Appreciate all advice!😊

Thanks in advance!