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Is it a meteorite, or is it slag?

16,778 subscribers a community for 5 years, 4 months

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A subreddit dedicated to identifying mysterious rocks or minerals.

/r/whatsthisrock Wiki. Example link to wiki to add to your comments (copy/paste):



  • Post several clear and detailed photographs of your rock or mineral, including close-up photos. An imgur album is preferred.

  • Indicate the size using a scale (e.g., a ruler, penny, or banana) for reference

  • Include information on geographic location, as well as location details, eg: A riverbed, a quarry, an old iron works.

  • Provide any additional interesting information about your specimen; including:

    • Color

    • Luster – What does the surface look like in the light?

    • Density – How heavy is it, for its volume?

    • Crystal Form – Any present?

    • Cleavage – If it is broken, what pattern does it make?

    • Tenacity – How tough is it? How cohesive is the material? Does it fall apart easily?

    • Hardness – What can scratch it or what does it scratch?

    • Transparency – Does it transmit any light or is it opaque?

    • Magnetism, Fluorescence, Odor, Streak Test






How do you ID a rock?

Start here:

MSA Rock Key

Rocks are made of minerals - go here next!

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