#my collection

A few of my lovely, lovely pieces of BIF. Banded iron formations are old! They’re some of the oldest rock formations in the world, in fact, speculated to be caused by cyanobacteria learning how to photosynthesize and subsequently producing oxygen in the oceans. This new oxygen caused iron in the water to form oxides, which settled to the ocean floor and built up from there seasonally and new blooms created new iron deposits.

The red bands are silicates, usually jasper and usually red, but they can appear orange or purple as well. The black bands are the iron, either as hematite or magnetite. Formations can be found all over the world.