Featured here is a medium size neat, cut piece of Banded Iron Formation from Canada. It may be used for a great specimen, or cut some beautiful cabs. The dimensions of this piece are: up to 1-1/2" width by up to 5-1/2" in length by up to 1-1/8" thick. The lot weighs about 1 pound. (This stone appears in our YouTube videos on Endlesscircle)
Banded iron formations (also known as banded ironstone formations or BIFs) are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness and extend laterally for several hundred kilometers. Almost all of these formations are of Precambrian age and are thought to record the oxygenation of the Earth's oceans. Some of the Earth's oldest rock formations, which formed about 3,700 million years ago (Ma), are associated with banded iron formations. {From Wikipedia, the free encyclopedia}