This banded Iron Formation has come from the Isua Greenstone belt in Greenland and is between 3.7 and 3.9 billion years old.
There are several lines of evidence which suggest that life might already have started by the time these rocks were laid down. Although BIFs are often indictative of oxygen changes due to the photosynthesis, the BIF in this sample is entirely due to metasomatism and is not biogenic.
The weight of this sample is 14g. This is a photograph of the actual item offered for sale.