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Thursday, April 2, 2009

Clark County Indiana Geodes

Here are the last of the pictures I found in the Kodak camera's internal memory. They are not of fossils but of a specimens that quite a few people look for on the Internet...GEODES. I think a number of members were picking up geodes at the quarry during the KYANA Geological Society field trip. Here are two that I opened up and contain quartz? or calcite?




3 comments:

  1. Probably quartz. Notice the concoidal fracture and hexagonal terminus of the xls.

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  2. Thanks for the information.

    I do not know much about minerals.

    I was with some of the KYANA members the other day and one said that quartz will scratch glass while calcite will not. I will try to find what box these specimens are in and test that.

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  3. ... quartz will scratch glass while calcite will not.

    Yes, calcite is 3 on the Mohs scale of hardness; quartz is 7. See this site:

    http://www.amfed.org/t_mohs.htm

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