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I found this rock in the desert. I found similar rocks that are crystal white on the inside, but this one is rough on the outside and all the others are smooth. Plus all the rough rocks doesn’t have a crystal whit center.

enter image description here

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closed as off-topic by Universal_learner, arkaia, Fred, trond hansen, Jan Doggen Jul 17 at 14:19

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Please review our rock identification guidelines to provide the missing information so that your question is both answerable and useful to new users." – Universal_learner, arkaia, Fred, trond hansen, Jan Doggen
If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ Please read this guide and improve your question. E.g. we do not know where the desert is... $\endgroup$ – Jan Doggen Aug 29 '18 at 14:58
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Your rock is almost certainly a form of quartz - either quartzite, which is metamorphosed sandstone or vein quartz, which is deposited by hot solutions underground. I think probably quartzite. Notice the grainy fracture - some minerals will break along flat surfaces but quartz does not (you may see flat surfaces from the crystal growth, but not from cleavage). Quartz can easily scratch glass and cannot be scratched by a knife. The orange colour is iron staining of the surface and shows why it is often important to break open rocks to identify them.

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