Rocks & Minerals B/C ID/Question Marathon

[sofossils]

Thanks DDH for teaching me something I didn't know. Identify all three minerals. (Click to Show Hidden Text)

[img]http://upload.wikimedia.org/wikipedia/commons/2/20/Galena,_Calcite,_Fluorite-274395.jpg[/img]

[solakmagic]

Thanks DDH for teaching me something I didn't know. Identify all three minerals. (Click to Show Hidden Text)

[img]http://upload.wikimedia.org/wikipedia/commons/2/20/Galena,_Calcite,_Fluorite-274395.jpg[/img]

Wow, beautiful!

Answer (Click to Show Hidden Text)

Galena, Fluorite, aaaaand Calcite

[sofossils]

Correct! It was a beautiful specimen

[solakmagic]

Identify (Click to Show Hidden Text)

[img]https://encrypted-tbn1.gstatic.com/images?q=tbn:ANd9GcRjd-L39FsMVLPEpbkuKTwkBsi0lbcZvLqy1i4HGeJ36_YuzVRg[/img]

[inluvwyth_WANTED]

I would say... (Click to Show Hidden Text)

Epidote or Apatite. The structure looks like apatite but the color (I know I know, we're not suppose to rely on this but...)

[solakmagic]

The answer isss (Click to Show Hidden Text)

Apatite!  I think that white scarring/ghosting/impurities/whatever you want to call it is really indicative of Apatite, though it can be confused with Sodalite.  A good example of what I'm talking about is on this specimen [img]http://www.charmsoflight.com/Images/Gemstones/Apatite%20rough%20crystals.jpg[/img]

Your turn!

[inluvwyth_WANTED]

Please give chemical formula (Click to Show Hidden Text)

[img]http://skywalker.cochise.edu/wellerr/mineral/hematite/6hematite-sliman3431a.jpg[/img][img]http://rruff.info/repository/sample/by_minerals/Magnetite__R080025__Sample__Photo__22213__M.jpg[/img]

[solakmagic]

Please give chemical formula (Click to Show Hidden Text)

[img]http://skywalker.cochise.edu/wellerr/mineral/hematite/6hematite-sliman3431a.jpg[/img][img]http://rruff.info/repository/sample/by_minerals/Magnetite__R080025__Sample__Photo__22213__M.jpg[/img]

Are these the same mineral? If so (Click to Show Hidden Text)

Hematite, chem form Fe2O3

[inluvwyth_WANTED]

No. They are not the same...Try again?

[solakmagic]

Then (Click to Show Hidden Text)

Hematite up top, Magnetite below!  Hematite Fe2O3, Magnetite Fe3O4 or more specifically Fe(2+)2Fe(3+)O4