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:

Anonymous said...

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

Fossil Detective said...

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.

Anonymous said...

... 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