What type of gem/crystal is this?

Going through my old rock collection from when i was young.  Found this one on a rooftop that was covered in rocks.  The crystals look brown.  What type of crystal is brown!??

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3 Answers

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  • Anonymous
    2 months ago

    Looks like calcite and aragonite but it's hard to tell with just looking at the picture. It would be best to do the acid test. If the crystals effervesce, then it is most likely calcite.

  • 2 months ago

    Some form of granite.

  • Ron
    Lv 7
    2 months ago

    I'm guessing they are calcite crystals (or some carbonate mineral).  I have seen both aragonite and calcite that color (color is from impurities of iron, probably).

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