Help with rock ID?

[rltn]

Could we ask for some help identifying these rocks, please?

My daughter is studying 2nd grade geology this year. She found these rocks in our yard in TN. We think one of them is black quartz but she is asking what kind of rock is underneath the crystals? Also, any idea about the red and white rock?

Thanks in advance!

 

[Bajahunter]

I think the red and white piece is a type of conglomerate called brecia.
Take a picture of the other rock all by itself. Fill the screen. That could be a nice example of smoky quartz.
The white crust around the darker material looks like plain old quartz. Do a hardness test.
Geodes or quartz in vugs is often layered with different types of silicon dioxide.

 

[rltn]

Thanks for the ID on the breccia! I found the articles on it very interesting - and it is close to what we had decided must have happened to make it (when we were reading our books).

Here are some larger pictures of the quartz. I noticed it is coming out the substrate rock in the back too - might try to clean out some of the extra material with a toothbrush to see if it is just mud? Even if it is just quartz it is one of the prettiest things in our collection. Little girl has been putting things away for a few years now found out in the yard and by the lake. We are finally learning more about them.

Thank you for your expertise!



Rock and shell collection

 

[bammer]

They both look like chert to me. The first one I think has been re-consolidated. The glassy spalls are a good indication on the second one that it is chert or flint.

 

[Eu_citzen]

I agree with Breccia. But don't mix up breccia and conglomerate - breccia is made from "crushed" rock that was "glued" together again. (think - faults)
Conglomerate on the other hand is made from compacted river sediments.

The second one I'm not so sure of. I'd like you to break off a corner and show us a "fresh" surface. Also do a hardness test and streak test.
Google both, if you or your daughter aren't sure of what that means.