TLDR: Cool rocks with unique stories (geologically and personally).
Banded Iron Formation (BIF, #1) is one of the coolest rocks on the planet (IMHO). Typically, it's >1 Billion years old and represents a time when early cyanobacteria would periodically oxygenate the atmosphere (red/ orange / rusty layers), alternating with low-oxygen, significantly iron-rich sediments from abundant volcanism (gray iron layers). Then, these deposits got cooked and deformed via deep, long burial, leaving beautiful patterns of squiggly solid iron (more or less).
The non-descript rock in the 2nd picture is amazingly even more remarkable than Banded Iron Formation (BIF). It's a conglomerate of PIECES of BIF. In other words, SOMEHOW several pieces of BIF (again, essentially iron) broke off (after already being deformed), were transported at least a little distance, and then were redeposited along with some sand. Then, that was all reburied and re-lithified (made into a rock again) to later be found by some ...
