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Purple stone, what are the likely contents?

  1. Apr 17, 2008 #1
    I found a purple stone and was wondering if it was a useful ore. All rock where it was found was the same type.

    Can anyone guess what type of ore a purple stone might be?
  2. jcsd
  3. Apr 18, 2008 #2


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    No. can you post a picture?
  4. Apr 18, 2008 #3
    I've taken one with my cellphone, but the colour is not reproduced at all, and also it's blurred.

    Is there any online database for the recognition of ores?
  5. Apr 18, 2008 #4


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    You can test various properties of minerals to get a pretty good idea of what you've got. See here: http://www.rockhounds.com/rockshop/mineral_id/

    For that to be of any use you'll have to be sure that you've got a sample of just one mineral rather than a rock that could be a mixture of many minerals.
  6. Apr 18, 2008 #5
    Bornite, a copper-iron sulfide, turns blue and or purple when it tarnishes. It has the largest percent of copper out of the major sulfide ore minerals.
    Last edited: Apr 18, 2008
  7. Apr 28, 2008 #6
    Are you sure about the type of your stone?

    There are many purple gems too.... Usually found as massive rocks like purple quartz (Amethyst) or a specific branch of Flourite & many more....

    A picture will solve the mystery.

    Here are some pictures of an amethyst;


    You can use the specifications given to test what the stone is. The most important one is its density which can be performed without any instrument. The picture is just too clasy & stylish in this link, but you will get an idea :)

  8. Apr 28, 2008 #7
    Thanks, it's not crystal-like at all. It's more like a rough rock.

    I think that may be what marble looks like in its natural state. If I get hold of a proper camera I'll take a picture, it may be some rare sort of marble.
  9. Apr 28, 2008 #8

    jim mcnamara

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    lapis lazuli varies from intense blue to purple. Some turquoise variants are light purple.
  10. Apr 28, 2008 #9


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    Marble is made mostly of calcium carbonate (like limestone and calcite crystals). It will fizz slightly in the presence of a weak acid. I've used dilute HCl in the past but I think vinegar does the trick too. Give it a go and see if you get any bubbles forming.
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