Here is a beautiful tiger's eye sample from the Proterozoic era of South Africa. Tiger's eye is a marine microbialite found in the Banded Iron Formation, which formed approximately 3.8 to 1.8 billion years ago during the Great Oxidation Event through the precipitation of iron in seawater. This slice exhibits alternating layers of magnetite as well as hawk's eye or tiger's eye. The latter are crocidolite pseudomorphs that likely underwent metamorphism later on. The significance of Banded Iron Formations in Earth's history lies in the fact that the development of cyanobacteria and the deposition of BIFs contributed to the enrichment of oxygen in the atmosphere. This oxygen enabled the evolutionary development of life forms, including mammals and humans.
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| | Location: | Northern Cape Province, Prieska, South Africa | |
| Size : | about 56 x 30 mm |
| Age: | Precambrian, Lower Proterozoic, Transvaal Supergroup (about 2250 Ma - 2300 Ma) |
