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I apologize for any errors in my pictures or writing. My first post.

[My guess quartzite. ![1]

This is the same rock from a different angle

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    $\begingroup$ Please make that one question per rock and add as much information to each after reading this guide $\endgroup$ – Jan Doggen Aug 26 '18 at 10:51
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    $\begingroup$ Scalebars and additional information would make it much easier... The location where they come from is quite useful for example $\endgroup$ – JulPal Aug 26 '18 at 14:54
  • $\begingroup$ Sorry about that, I will attempt to follow Jan Doggen's suggestions. Thank you for replying. $\endgroup$ – Paul Sep 2 '18 at 12:30
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The first two images look like banded calcite to me. The rock appears to have distinct cleavages, no clearly conchoidal fractures, and a slightly waxy luster on the weathered surfaces. Sometimes this type of rock goes under the term onyx but traditionally onyx is a type of chalcedony. If it is banded calcite a typical knife will easily scratch the surface, additionally it would fizz with some muriatic acid (or dilute HCl). If it is type of chalcedony, then knife will have a harder time scratching the surface an may not if the knife is on the soft side. Also the acid will not react with the stone.

Jan Doggen's suggestion will help you get better results for the other stones.

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  • $\begingroup$ Thank you for taking the time to answer, I will upload the images following Jan Doggen's suggestions. Hopefully this will provide everyone with more information. $\endgroup$ – Paul Sep 2 '18 at 12:31
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First and second one seems to be chalcedony (because it's banded). Igneous. Unlikely, metamorphic.

Third and fourth picture apparently have garnets (the red dodecahedrons). I'm betting my buttons it's a metamorphic rock.

(more experienced fellas, please correct me if I got something wrong - I'm still learning)

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  • $\begingroup$ I am way less experienced than you Matheus, thanks for taking the time to reply. I think I need to improve my images and provide more info on each. Thanks again. $\endgroup$ – Paul Sep 2 '18 at 12:33
  • $\begingroup$ Important addendum, I have spoken to my mineralogist teacher and he said that is definitely NOT an amphibole. $\endgroup$ – Matheus Sep 5 '18 at 13:44
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Quarts and most of all agate. Where did you find them? That was just my guess.

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  • $\begingroup$ I am currently in Thailand and found some of the rocks in a garden centre which means they may have come from anywhere, but most likely somewhere in Thailand itself. The first rock was given to me by one of my students here in Thailand. Again I am not 100% sure that that is where it originated. $\endgroup$ – Paul Sep 2 '18 at 12:35

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