r/geology • • 16d 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

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 • • 7h ago

Information Looking for a US laboratory that can test geological samples for Osmium (Os) and Iridium (Ir)

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32 Upvotes

Hi everyone!
I’m hoping someone here might be able to point me in the right direction.
I’m looking for a reputable laboratory, preferably in the United States, that can perform quantitative analysis for Osmium (Os) and Iridium (Ir) in solid geological samples.
The material consists of dense, iron-rich, cube-shaped specimens discovered embedded in hard rock during gold exploration.

We had some preliminary handheld XRF readings suggesting the possible presence of Os and Ir, but we understand those results may not be reliable. We’d like to have the material independently tested to determine its actual composition.

I’ve contacted several commercial laboratories, but so far, finding one that can specifically quantify osmium in this type of material has been surprisingly difficult.
I’m not looking for a basic XRF scan or mineral identification alone. Ideally, I’d like a proper quantitative assay that can confirm whether these elements are present and at what concentrations.

Does anyone know of a laboratory, university facility, or specialist that offers this type of testing? I’m happy to pay for the analysis.
Any recommendations would be greatly appreciated. Thank you!


r/geology • • 9h ago

Scientists discover oxygen trapped deep inside Earth’s magma, possibly explaining the rise of early life

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20 Upvotes

Molten rock may carry an oxygen reserve that standard chemical calculations overlook. High-pressure experiments show that basaltic melts exposed to oxygen-rich conditions can retain substantial extra oxygen, potentially adding a missing component to models of Earth’s interior.

The study in National Science Review combines laboratory measurements with atomic-scale simulations. Yanhao Lin and Ho-Kwang Mao of the Center for High Pressure Science and Technology Advanced Research, known as HPSTAR, led the work with collaborators. The team included Haiyang Niu of Northwestern Polytechnical University and Wim van Westrenen of Vrije Universiteit Amsterdam, with Yongjiang Xu as first author.

The results raise a larger possibility: some rising magmas could transfer oxidizing power from deep reservoirs toward the surface. Establishing that capacity, however, is different from demonstrating how much oxygen natural magmas actually carry or release.


r/geology • • 19h ago

Meme/Humour Magma Joke

118 Upvotes

A clip from my volcano comedy special, here's the full show: https://www.youtube.com/watch?v=72IwnxnejfE


r/geology • • 21h ago

Field Photo How does this happen?

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164 Upvotes

I understand the rocks can split but this looks like a chunk was taken out and it looks like a perfect split. But the other lines and cracks in the rock aren’t not perfectly straight. Is this natural or human made?


r/geology • • 10m ago

Basalt or Diabase

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• Upvotes

I was wondering if the inside of these rocks looks like basalt, and looks like a pillow. Is it pillow basalt? I was told they were cobblestone and became rounded by water, how can it all be the same shapes and have the iron on the outside if it washed down a river? Upstate South Carolina


r/geology • • 16h ago

Information Nearly 600 California earthquakes help validate models that forecast next-day seismic risk

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21 Upvotes

r/geology • • 18h ago

Strange formations near Mount Amiata

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11 Upvotes

While exploring the Italian landscape with daevorn-maps, I came across this hill not far from Mount Amiata, which has a curious pockmarked surface. I’m not sure whether these are boulders or holes, but in any case, the pattern seems far too regular to be a natural formation.

Mount Amiata is a Pleistocene volcano, so this could be the result of volcanic eruptions.

Does anyone have any ideas or explanations?

Thanks!


r/geology • • 16h ago

Joints in my local bedrock produce heart-shaped rocks

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8 Upvotes

My mother first noticed these when I was a kid, but had no idea why they were this way. It wasn't until I got some geology education, and learned about the joints in my area's bedrock that I figured out the cause. Joint orientations vary, but it's fairly common to find orthogonal or nearly orthogonal joint sets.


r/geology • • 1d ago

Field Photo Discussion of the formation of the mineral

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94 Upvotes

Garnet in Limestone. So we are having drilling exploration in the limestone terrain and we found garnet patches on limestone. What could be the reason ? The terrain is of Granulite region as the basement rock but we are yet to hit the basement rock ?


r/geology • • 18h ago

Sneak preview! New edition of the classic book Geologic Wonders and Curiosities of Missouri

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2 Upvotes

r/geology • • 1d ago

Map/Imagery G.K. Gilbert's Great Bar at Stockton, Utah, built by Lake Bonneville [OC]

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27 Upvotes

In 1877 Grove Karl Gilbert, a geologist with the Powell Survey, passed through and recognized this ridge of gravel as a giant sandbar built by a lake that no longer exists. Waves and currents on Lake Bonneville piled it up in the strait between South Mountain and the Oquirrh Mountains.

Three years later he came back with the U.S. Geological Survey and mapped it in detail as "The Great Bar at Stockton, Utah."

This is my own render of the bare-earth lidar. The bar is the long curved ridge running from the left edge to the middle, where a road and rail line cross it.

  1. Bare-earth lidar: the Stockton Bar curves in from the left edge
  2. Air photo of the same area, October 2021

Numbered pins on picture 1:
Pin 1: Crest of the Stockton Bar
Pin 2: Road and rail cut through the bar
Pin 3: A quarry pit in the bar

Lidar: USGS 3D Elevation Program (3DEP), public domain.
Imagery: USGS The National Map (NAIP Imagery service), 2021, Public domain.


r/geology • • 1d ago

Found some sweet crenulation

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72 Upvotes

r/geology • • 1d ago

Information Footprints in the (white) sand: Humans experienced abrupt environmental shifts during the last ice age

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60 Upvotes

r/geology • • 1d ago

Meme/Humour For humans (and magpies) it is impossible not to like rocks.

100 Upvotes

r/geology • • 1d ago

Field Photo Cool rock I found

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25 Upvotes

Found this cool rock on a construction site in Ohio. My sedimentology is extremely rusty. My guess is this originally from an area in a floodplain near a river or something since it appears to alternate between gray sandstone and brown mudstone.


r/geology • • 1d ago

Ancient volcanic eruption brought population collapse and coastal growth to Japan

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21 Upvotes

Some communities declined sharply after one of the largest volcanic eruptions of the Holocene, while others continued growing surprisingly close to the devastation. A reconstruction of prehistoric Japan’s population patterns suggests that catastrophe produced no single outcome.

Conditions before the eruption, access to recovering ecosystems and possible movements of survivors all shaped what followed. The evidence complicates an archaeological debate often framed as either total collapse or straightforward survival.

The international study, reported in Science Advances, examines the Kikai-Akahoya eruption about 7,300 years ago. Enrico Crema of Cambridge University led the analysis, with Lund University archaeologist Peter Jordan as senior author. Their team modeled changes in archaeological radiocarbon dates across Japan. They then compared the reconstructed trends with pottery, tools, settlement evidence and volcanic ash deposits.


r/geology • • 1d ago

Really struggling to understand SiO_2 and SiO_4

7 Upvotes

Normally I don't need any extra help but for some reason I just keep getting stuck on this topic. I understand that SiO_4 is the basic building block for the silicate minerals, but for some reason when I try and think of SiO_4 being inside os SiO_2 it throws my brain off. Why is SiO_2 considered SiO_2 when it has Si_O4 inside of it, because if you took a single compound of SiO_2 it would be SiO_4 meaning for each silicon you have 4 oxygen but the formula says for quartz you should have for each silicon 2 oxygen. I genuinley just want to understand why this is the way it is and why it makes sense, any explanantions or resources on this are greatly appreciated.


r/geology • • 2d ago

Look at these beautiful curbs

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397 Upvotes

In my town we got beautiful curbs of different types. Im assuming gneiss and granite but not sure. My favorite is the first stone, looks like a piece of art.


r/geology • • 1d ago

Field Photo This piece of chalk i pulled out of the ground

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4 Upvotes

I have done my geology research and I live on the boundary of the Eagle Ford Shale and Austin Chalk. The chalk here has layers of Calcite that precipitated out of the other rock forming these layers. I have found out the chalk/shale is of Jurassic age. Also I have a big collection of amorphic Calcite that I have found around my neighborhood.


r/geology • • 2d ago

Found in wooded area. What could have caused this formation?

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44 Upvotes

Note: the lines on the rocks don’t all go in the same direction. Some vertical and other horizontal


r/geology • • 1d ago

TU Bergakademie Freiberg for geology in 2026!!

0 Upvotes

Does Freiberg have strong industry connections in mining, mineral exploration and economic geology? Are international graduates finding jobs after completing their Master's?


r/geology • • 1d ago

TUM (Technical University of Munich) for geology in 2026!!

0 Upvotes

How good is TUM's MSc in Engineering Geology and Hydrogeology for getting a job in Germany after graduation, especially for international students?


r/geology • • 3d ago

Minas Tirith, or Sand?

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133 Upvotes