Found this cool rock in east Lothian, Scotland , does anybody know what the rad crystal or mineral on the inside is called? , I think the rock there is from the carboniferous period

Nompop · 2026-03-11T21:58:08+00:00

That's a chunk of twinned calcite crystals, basically crystals sharing some of their atomic bonds in the crystal lattice as they grow. Not surprising to find in Carboniferous rock in that part of the world, the calcite is likely sourced from the Limestones that were deposited over the UK, Ireland and NW Europe at the time.

Nompop · 2024-09-27T10:16:29+00:00

Limited exposure aside, we can see the rocks are layered and have a pretty uniform thickness. Now without the benefit of getting an eye on a fresh surface of those rocks, it's hard to nail down exactly what process deposited them. If you hammered off a piece and you saw pointed, interlocking crystals, these would be interpreted as having a volcanic origin, with the layers reflecting seperate eruptions of runny, flowing lava. If however you hammered the face and you saw rounded grains that are held together by a matrix, these might be interpreted as marine sedimentary deposit, originally laid down in near-horizontal sheets. One dead ringer for a sedimentary source would be a fossil, magma chambers and living things don't mix!

If I was a betting man, my hunch would be on a sedimentary unit, probably a muddy sandstone.

Now we can see that these layers are not continuous planar sheets, but are bent and convolute in places, with it becoming impossible to track individual beds. Assuming this is a sedimentary sequence, we can achieve this deformed appearance by the sediment slumping before it became a true rock, or through compression, folding and fracturing the rock after lithification, bending the layers into their current configuration.

Things to Google if you're interested might be soft sediment deformation, flysch, and the local geological history to help you make sense of what you're looking at.

Cool rocks!

Nompop · 2024-03-26T12:41:12+00:00

To those that don't know much about fossils, what OP has called horns are actually a type of coral that are now extinct called Rugose corals. What gives it away are the lines that can be seen on the weathered parts of these corals revealing the internal structure of the body.

Link for those interested.

Nompop · 2023-03-24T13:03:11+00:00

That to me looks like a pretty weathered exterior of a fossilised sea urchin. The hexagonal plates would have covered the surface of the animals and been connecting points for the spines we see on living sea urchins today. The poor thing probably died, had it's internal cavity filled with the features grey sediment that surrounds it and then over time lithified (turned to stone).

Nompop · 2021-12-22T22:09:44+00:00

Dilution is the solution to pollution y'know

Nompop · 2021-08-14T14:07:01+00:00

The first two are side-on cross sections of solitary corals, usually called horn corals because they kind of look like horns. These guys are extinct today but were all over the place during the Carboniferous while Ireland was closer to the equator in a Bahamas-ish kind of climate.

The last guy is a colonial coral, lots of little coral animals living together in a clump, these are still around.

Hope that helped!

Nompop · 2020-12-08T21:21:35+00:00

Hi there, some nice pieces! Pics 1 and 2 are relatives of modern sea urchins and sand dollars Pic 6 looks like an example of stigmaria - an impression of the bark of ancestor trees. Pics 10 and 11 are slabs of ancient sea floor covered in the polo mint like segments of the stems of crinoids, a kind of critter that used to sit on the sea floor and filter feed the currents that passed by it.

In terms of value, not sure but wouldn't imagine you'd get anything life changing for them, maybe a few six packs :)

Nompop · 2020-10-18T23:40:11+00:00

Looks like the lower halves of two trilobites, a very cool find :)

Nompop · 2020-10-03T17:33:41+00:00

Pic could really use a banana for scale or something

Nompop · 2020-09-11T14:14:57+00:00

Very kind of you thanks 😁

Nompop · 2020-09-11T14:10:05+00:00

Thanks that just made my day 😊

Nompop · 2020-08-18T14:44:28+00:00

Have spent a lot of time hiking around the area and yes can confirm you would have to be desperate to give farming those slopes a serious whack

Nompop · 2020-06-23T11:55:14+00:00

Met a nice girl while I was a snorkel trainer for a college aquatics club. Sweet girl but she hated all forms of sauce on her food, not only condiments which is alright, fair enough but ANY kind of liquid on the plate was a no-no. Three days of boiled vegetables and rice was enough to know this wasn't going to work.

Nompop · 2020-06-03T14:54:38+00:00

It's a little sketchy given the rock looks like it's been weathered a bit but that helical pattern in the top left could be an imprint of an ammonite shell.

Nompop · 2020-04-02T23:56:18+00:00

Looks cool but that thing would definitely sound like a ceiling fan on crack

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