Is this volcanic glass running through quartz

Posted: Mon Feb 20, 2012 1:31 pm

This is not iron, it gives off no metalic signal on a metal detector. So, I was thinking it was volcanic glass(obsidean), running through this peice of quartz that is about alitte over 2" long. This quartz came from my yard, right from the surface(I seen it and picked it up).

If that is what it is, I would think this would be a very good sign for what kind of ground I am sitting on...? Thanks.

Posted: Mon Feb 20, 2012 5:53 pm

ilmenite. very common mineral for the slate belt. Had a quartz crystal spot in Chatham County that was full of it. Def. in the group of good indicators for gold, probably lots of pyrite and limonite, and hematite nearby.

-Dave

Posted: Mon Feb 20, 2012 6:28 pm

greendave wrote:

ilmenite. very common mineral for the slate belt. Had a quartz crystal spot in Chatham County that was full of it. Def. in the group of good indicators for gold, probably lots of pyrite and limonite, and hematite nearby.

-Dave

Yes Dave, TONS of hematite...per pan its about 25% magnetite(coarse) and 75% hematite(fine) in the actual creek(which is in a small valley). Mineralization is off the charts..

Posted: Mon Feb 20, 2012 6:49 pm

I agree with ilmenite as well. Try to streak it on some white porcelain tile it should leave a black streak.

Posted: Mon Feb 20, 2012 6:53 pm

Astrobouncer wrote:

I agree with ilmenite as well. Try to streak it on some white porcelain tile it should leave a black streak.

Thanks guys. It does seem to be ilmenite(did streak test).

thanks both of you.

Posted: Mon Feb 20, 2012 6:54 pm

I'd argue that 75% is actually ilmenite in your pan, or your mineral specimen is hematite (the specimen you found is from the source that has since broken down and eroded into the alluvial), the two are almost indiscernible. However, the streak for ilmenite is a brown-black, while hematite is an unmistakeable brick red color. Hope this helps, either way, unfortunately it's definitely not obsidian, as it is not found in NC or anywhere in the eastern US for that matter.

-Dave

Posted: Mon Feb 20, 2012 6:55 pm

you guys respond too fast Smile

Posted: Mon Feb 20, 2012 7:01 pm

greendave wrote:

you guys respond too fast Smile

hmmmm, we are talking on a low end..a half cup of non magnetic black sands per 14" sample pan. It is very very fine..

I never thought about it being that though...I thought it was hematite(seems to be to much of it) but I guess I will have to investigate about what I am thinking is hematite. You are probably right though(you guys know alot more about the minerals than I do).

Thanks.