Large Tiger Iron Slice

An amazing geologic treasure over a BILLION years in the making. Banded Tiger Iron consists of the earliest known fossilized organisms and the oldest known rocks on Earth! This rock formed on the ancient sea floor roughly 2 to 2.5 BILLION years ago and comes from the Ord Ranges, Cleaversville Formation of Western Australia. It consists of alternating layers of iron oxide (metallics and reds) and microcrystalline silica in the form of Tiger Eye (golds). Heat and pressure from the Earth’s movements dramatically folded the bands in the rock.

Formed during the Archean Eon, (Archean from the greek meaning “beginning” or “origin” for the first start of life), it is believed that the Earth resembled a water world, with most of the continental crust hiding under a very deep ocean. The atmosphere lacked free oxygen, so when the first micro-organisms (cyanobacteria) photosynthesized, it greatly increased the oxygen content in the oceans. Banded Iron slabs are believed to be derived in part from the remains of these micro-organisms.

As dissolved iron and silicon rose from depths in the ocean, it interacted with the more oxygen-rich water (produced from the cyanobacteria photosynthesizing) to combine and make insoluble iron oxides and silica, which came out of solution as a fine-grained sediment. As these sediments fell to the sea floor, it created accumulating layers of iron oxide and silica-rich sediments in alternating bands on the ocean floor. This process repeated for nearly a billion years and can be seen in all its geologic glory in slabs like this!

A large slice of this rock formation has been cut with one side polished to a high gloss finish with the top and sides left in their natural state.