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So there are ringing rocks in various places of the world, which ring like a bell when struck. Why? What is going on with the properties of the rock that make them ring? Is this replicable?

Are there any scientific papers on this subject where I could learn more?

Example: https://en.wikipedia.org/wiki/Ringing_rocks

Hiya, my grandfather was a geologist and we recently found these in his collection would anyone be able to help ID these? Thank you so much in advance 😊

I was originally thinking flint, but there's that weird iridescent patch on the back, it was found at the base of the Tatra mountains near a water source, near zakapone in poland. It scratched glass, aluminum, and my fingernail easily.

I’ll begin by stating that English is not my first language, and am studying Mineral and Metallurgical Engineering at a famous mining/geology school. As part of our sophomore year cross-departmental courses, we have a course in the geology department called Geology for Engineering and Sciences; common with sophomores from the geophysics and mining departments. The course structure is really nice, covers mineralogy, mineral and ore formation, Bowen’s reaction series; fold, block mountains, landscapes and contour/relief maps, palaeontology, seismology, and continental drift. That is of course tangential but while teaching us continental drift and the evidence for it, he strayed into the idea of climate change denial and how he believed climate change and global warming is a highly exaggerated idea. He brought up Michael Crichton’s famous book denying climate change, State of Fear; and while he did admit that there are petroleum and coal lobbies supporting this agenda, his counter to us was also that the idea of climate change and global warming being real phenomena to concern us would greatly help the electric and renewable energy/solar energy enormously. He pointed out how in a number of inland glaciers, ice buildup data during a series of years has been higher than the ice that actually melted. So there was a net gain of ice in these glaciers, opposite to what global warming theorists might suggest. What do you guys think? He’s a really respectable person, done his higher studies in Virginia Tech and the Royal School of Mines. Really fun to study from. I discussed this with him afterwards for quite some while, he had essentially the opinion that a full transition from petroleum to renewable energy is impossible and idealistic. He even said how there were theories suggesting petroleum itself is not fossil fuel per se, but rather derivatives of meteorites that landed on the earth. What are your opinions? I’m against the climate change denial movement and I know that all of us have watched that Hbomberguy video discrediting the Ben Shapiro argument against climate change; but he really did make a convincing argument.

The picture is of Mt. Hood taken by me (and no, I don't plan on giving Mt. Hood back 😠)

I've been thinking about this question while contemplating the short mountains in Oregon comparatively to Washington, as well as the collapse of Mt. Saint Helens and Mt. Mazama.

Hi, folks. I rockhound a bit for exercise and for the neat agates and jaspers I find along a stretch of rocky beach. The green rocks I find are so mesmerizing and I have no clue what they are. My guess is some types of jasper or chert. Am I right that copper gives these the green colouring? Are these familiar to any of you?

Chunk of flint from England, what are the arrowhead shapes? One is very defined, you can feel the grooves with your finger, one is perfectly smooth like it’s part of the rock.

It was suggested on whatisit/r that I post these pics here. Found in the Huron River/Argo Dam Pond, in Ann Arbor Michigan USA. It is about 20x20 feet in diameter, in 5-6 feet of water. Hard to see unless you are directly over it and the sun is shining. Is it eroded sandstone that used to be exposed before the dam was put in and raised the water level?

I would like to know about how these shapes were formed.

They remind me of dendrites as well as how frost sometimes forms on my car window.

To be clear, all of these fantastic shapes are indentations in the rock, which I called fracture lines even though I am not certain that is the correct terminology.

In the OP I called this jasper and I still think that is correct, however the few replies I had all said it was not.

Here is what I believe to be a concretion I found last year. Got a bunch of jokes about it being an old petrified cow patty lol. I was hesitant to open it up but I saw cut it the other day and was curious about what I’m looking at. There’s some cool veins in it, there is a “granite” like looking vein but not entirely sure what it is exactly. Then there is some like fools gold appearing metallic veins in it. Couple areas that look like some quartz or crystalline structure. Just posting to learn about it if anybody knows.

If something was laid down a thousand years ago, how deep would you expect it to be in a mountainous region similar to the Cascades?

New to Reddit, so lmk if there are particular conventions I'm missing.

Could this be cinnabar?

Vu que je les creuse depuis longtemps, les études disent qu’ils sont de Éocène d’autres disent Crétacé. Bien que je pose la question je savais déjà que la plupart des amateurs de fossils ne connaissaient pas ces belles plantes. 🌱
Bon fin de semaine

I feel like I’ve been loosing my mind lately. Around two weeks ago, there was a 5.5 magnitude earthquake in my city. It was in the afternoon, I was laying in my bed and suddenly everything started to shake for approximately five seconds. I live in a fifth floor and it was relatively strong, but nothing super extraordinary. Nevertheless, it’s the first time in my life I’ve truly felt an earthquake to its full extent.

Anyways, the thing is that almost every night since I’ve been awaken in the middle of my sleep, and I’ve noticed these very subtle vibrations that can last up to two minutes. They are very, very weak tremors, so it’s pretty much impossible to record them and sometimes I have to stop breathing to even feel them. Other times, these are the equivalent of sitting down in a massage chair.

These usually occur at around 2:00-4:00 am, and I’ve thought that perhaps because I’m at such an hypnagogic state of mind when I am awaken during these hours, maybe I’ve been hallucinating everything. Last night, however, I felt them and forced myself to a fully awake state, and I could still feel the vibrations for around 15 to 20 seconds.

If this can really be attributed to seismic activity, maybe the reason I only feel them in bed is because my entire body is laying down and has greater surface area in contact with the ground. Maybe this happens all throughout the day on a daily basis, we just don’t typically feel it because we’re not in a recumbent position.

Does my theory have scientific validity or am I tripping?

I found some rocks recently in Spain (Alicante).According to Chat gpt they could be 3-20 million years old.is this true? I would really appreciate some information.thank you 🙏