r/Rocks • u/Piqka143 • 25d ago
Discussion What kind of rock is this ?
Found in Ohrid Lake Macedonia
Pics: back and front of the rock
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u/MoreInfo18 25d ago edited 23d ago
Good question. Do the sides have any interesting patterns? Also, maybe photos of the stone after it;s been wet might bring out something helpful.
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u/Piqka143 25d ago
The other side is on the next slide b
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u/MoreInfo18 24d ago edited 24d ago
I meant the thinner edge sides. Also, some things might contrast more if the rock is wet. I do think, it might be a fossiliferous lime stone, but not sure what might be folssilized within. It’s probably fossilized coral
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u/Piqka143 24d ago
As soon as I get home, I will post photos of the sides because I’m also interested too
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u/Piqka143 24d ago
As soon as I go home, I will post one picture of it wet, and also the sides and definitely better lighting
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u/NotSoSUCCinct 25d ago edited 25d ago
Looks like small-scale boxwork. The host rock fractures under the surface, groundwater or whatever fluid has dissolved minerals, the fluid fills the space of the fracture, the dissolved minerals precipitate out, the rock is exposed to the weathering conditions where the host rock is less resistant so the host rock weathers at a faster rate preserved the form of the stronger minerals.
This is a common feature in caves and hydrothermal settings. Any environment that is conducive to dissolving minerals, usually by readily soluble minerals, composing the bulk of a formation (limestone - CaCO3) or a very hot environment (quartz intrusions, Yellowstone hotsprings are supersaturated with silica [SiO2] but cools so rapidly at the surface it makes cinter [that white-gray stuff around springs] instead of quartz. Underground, where things cool more slowly, crystals will form).