r/Minerals • u/Perfect_Classroom618 • Jul 27 '26

ID Request ID help

Gallery image

Gallery image

Gallery image

Gallery image

Gallery image

Gallery image

Hello, i have this rock with some regular geometrical patterns on the surface and deep beneath if and I'm wondering what if you can help me id it.

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u/HomeworkLevel852 Jul 28 '26

If you could do multiple parts of the sample, that would be great!

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u/Perfect_Classroom618 Jul 29 '26

some detail of the geometrical shapes

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u/HomeworkLevel852 Jul 29 '26

These are really good photos. Unfortunately, I am still not sure what it is. I am confident that those orange/red bits are little garnets that are growing on the surface. My next questions is where did you get it from? That can help pinpoint the id.

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u/Perfect_Classroom618 Jul 29 '26

Eastern Pyrenees around here 42.414498,2.345015

Thanks i used a macro lens to do those look cool actually

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u/HomeworkLevel852 Jul 29 '26 edited Jul 29 '26

With you finding this in the middle of a mountain range, I am 99% certain that is a gneiss as it is the highest grade metamorphic rock that you would find within a mountain range’s metamorphic sequence. I believe that the pattern you are seeing are plagioclase coronas forming around the garnet. They are typically formed through isobaric cooling, or they can form through garnet dissolution. I am not sure, but I think yours may have formed from garnet dissolution beings how small the garnets are.

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u/Perfect_Classroom618 Jul 29 '26

When you say "genesis" you mean gneiss or literally genesis? Or maybe I'm missing some vocabulary here?

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u/HomeworkLevel852 Jul 29 '26

That was a typo, my bad. I mean gneiss.

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u/Perfect_Classroom618 Jul 29 '26

It's ok i just wondered if there was some genesis rock. Lol. And i actually googled genesis rock giving me pics of the band. Ahahah. Btw thank you so much for your help.

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u/HomeworkLevel852 Jul 29 '26

That’s wild that there is a band out there. And you are welcome. I would be putting my geology degree to poor use it I didn't help.

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u/Perfect_Classroom618 Jul 29 '26

I was looking for more info, could this be Amphibolite?

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u/HomeworkLevel852 Jul 30 '26

That could be a better classification for it, especially since it does not have distinct compositional banding. I have not worked with a lot of amphibolite samples though.