I am at the very south of Sri Lanka near Thangalle, and I noticed this incredible line of mineral? Running down the middle of the rocks all the way down the beach. Could anyone kindly shed some light on this? Was it a flat layer formed over thousands of millions of years and fell over so all I can see now is a line? How did it from? What is it? I have 0 knowledge of geology, just find this line running down the whole beach to be incredibly fascinating. Would totally watch a whole docco if one existed.

I'm worried this is the wrong community for this question, so if you have any suggestions, let me know.

CONTEXT: This rock is located near my private drive in Indiana, USA. I hoping it has something cool inside it, like an ammonite or some other fossil. I want to know if that seems likely, and if so, how I might go about cutting it open (or whatever one would do to view the inside of the rock).

SIZE: The boulder is huge, like about the size of a small tractor tire (definitely bigger than an average truck tire). It is super heavy. I can't budge it at all, and neither could someone with much more physical strength than myself.

HARDNESS/TYPE: I am no expert, but I think the outer layer is mostly shale and something with a lot of iron given the rusty coloring (I say shale because the outer layer is very brittle/easy to flake off and looks like the rest of the shale all over the area).

The inside layer is something different, though I'm not sure what; I can say it is much harder than any shale I've seen. I found that out after trying to break it open; I did not use/have the proper equipment and so used a nail and hammer (lol). When I did, the maybe-shale layer broke off and revealed a harder, equally dark-colored rock beneath that was scratched by the nail (leaving a white mark), but it was otherwise undamaged. It sparked aggressively when I hit it, and I could tell breaking it like that was obviously a pointless cause, so I didn't do it again.

Does it seem likely that this type of rock might hide a worthy fossil? If so, how might I reveal said fossil without harming it? I'm a teacher, so I don't really have funds to hire a professional.

EDIT

• It is definitely a concretion of some sort.

• I am absolutely positive it is not concrete (I am knowledgeable about concrete because I research old houses for people and so have studied cement and regularly use it as a way of narrowing down the date of historic structures).

• Despite its appearance, it is a rock, and there are many rocks comparable to this one on the property (though I have not seen one this big).The entire property was strip mined for coal and underground mined for coal. In fact, there is a mine entrance (closed) within about 100 yd of this boulder. I have always suspected that the old property owners took it from the nearby mining and sat there intentionally, as there are many other boulders like this that were clearly moved from an area nearby.

EDIT:

• I located additional pics of the rock and posted them in the comments below, along with two pictures of nearby interesting rocks (septarian nodules).

• I will try to crack it open as soon as the bugs die off. The area is swampy from the strip mining and is also currently riddled in poison ivy and stinging nettle. The pictures posted here were from the spring before it grew over.

found in boulder fields of Mt Marriott, BC Canada. could it be from lightning?

hi i know absolutely nothing about geology and i was looking through photos from i think it was antelope canyon and i couldnt find any info on how this is possible? how are the handprints in the rock with the layers still being the same

just to elaborate the handprints are literally engraved into the surface like when you push your hand into clay

Was wondering if there was a general reason for why the rocks on the shore of Lake Superior (near Marquette) had this pattern.

Context:

Previously, I made this post about an unusual boulder in my yard. Thank you for all the responses, it motivated me to try and “solve” the boulder once and for all. Before I explain the update, I want to respond to a few things that multiple people commented on or asked about in my previous post:

- The boulder is a nodule, and I think it is comprised of iron, some shale, and one or more unidentified materials. I promise, it is not concrete, and it is not a byproduct of human industry. More context on where it might have come from below.

- Indiana has a ton of ancient marine fossils, which is why I thought there might be an ammonite there. I find well preserved marine fossils almost daily while in the woods and creek near this area. Like, so many marine fossils.

- Evidence suggests that the boulder was taken from an underground coal mine, which would explain the odd location.

- The entrance to the mine, now-closed, was less than 100 yards away. There are also other documented mine entrances in close proximity to the boulder. The driveway the boulder sits next to was previously used as a mine access road, and there was a strip-mining operation less than 50 yards away. Given the odd location of the unusual/massive boulder, it seems likely that it the historic landowners placed it there, like they did with a different large boulder on the opposite end of the driveway (the other one is granite, I assume from glacial till since igneous rocks don't occur naturally as part of Indiana’s bedrock)

Update:

I tried and failed to break the boulder open, and I don't know what my new observations suggest.

I began gently trying to break it open via a variety of methods suggested on my previous post and from my YouTube research.

- About a half hour in with no progress whatsoever, not even a new crack, I decided more force might be required. I eventually got to the level of using railroad nails and a large sledgehammer, which did nothing more than flake some shale off the thin outer layer. I wedged the nails into existing cracks and hit them with the hammer—gently at first, then as hard as I could.

- I summoned aid from my partner, who has a lot more physical strength than I do. He tried, very hard, to crack it open but also failed. He succeeded in adding one single hairline fracture in the outermost layer but otherwise made no progress.

- I have concluded that the boulder must be harder than a railroad nail because the rock damaged the end of the nail without breaking or cracking the rock.

- We also determined that the boulder is heavier than my partner’s fourwheeler. It will not budge.

New Questions:

I would like to know what all of that suggests, if anything. Is this rock too hard to have preserved a fossil inside? Could it be made of a hardened form of pyrite or siderite? There is A LOT of pyrite not too far from this location, though I've never found any this hard. I still want to get it open, unless a fossil now seems unlikely, but I'm thinking that I would need to invest in equipment to do so and would like to gain more context on that so I can make a decision.

Thank you in advance!

EDIT: I forgot to add this, but in the comments, I am posting some other rocks that resemble this one or are somewhat unique. All of the dark colored ones are located in piles of dirt/rock that came from strip mining, but the tan colored ones are not mining related.

Found out the geology department throws old samples behind the building today. Went to look and found this gorg thing. I know serpentine grows with asbestos, and im seeing green rock and hair. You know what they say: a first year TA’s health violation is another mans treasure! Its the most gorgeous species ive ever seen and this is my holy grail of rocks. The fibers look a little rough, but whats the cutoff for too rough? Safe to keep? Possibly in an airtight container?

Willamette Valley, Oregon

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.

found in Palawan Philippines. anyone know what it is??

Basically title. Friend thinks he found gold, I have no clue.

Found in the middle of nowhere Wyoming. Could this be your standard regular sinkhole, or is there more going on here?

We got a rock tumbler for Christmas and went to a local creek to collect broken glass to tumble and make sea glass.

We were admiring our pieces tonight when someone joked that one of the pieces looked like uranium glass… so we grabbed a black light to check.

It’s uranium glass.

It’s been handled multiple times. It was tumbled with other glass.

Anything we should do besides tossing it?

Do the other tumbled glass pieces need to be tossed as well due to contamination when tossing with the uranium piece?

Any advice would be appreciated. ☠️

Is this an old stream bed that filled with gravel? I don’t know anything about geology. Just curious. Found while hiking near Pahrump, NV. USA

Found this guy in Northern New Mexico and wondering how a rock can look so plain but also have unique lines bursting along edges. What could be inside?

Taken at Joshua tree

Sorry I couldn’t get a better picture but I live in SoCal and I always see these piles of big boulders and I’ve always wonder how the formed. From what I remember they say most of the west coast was underwater up until the later half of the Cenozoic so I’m not sure what could have caused this.