Marra Mamba Tiger Iron comes from western Austrlia and dates to 2.5 billion years ago, during the Precambrian Eon. This is close to some of the oldest rocks on earth, at about 3.5 billion years ago. Marra Mamba is a variety of tiger iron with reds, blues, yellows and golds. The iron stone formed during a time when there was little oxygen in the atmosphere. Oxygen-producing bacteria that lived in the oceans released oxygen into the atmosphere, which dissolved into sea water. Iron from underwater volcanoes reacted with this oxygen, producing iron oxide. This resulted in banded iron formation, layers of iron oxide (hematite) with chert. The layers underwent alteration to form the mineral riebekite, a fibrous asbestos mineral. With further alteration in mountains, the riebekite was replaced with silica, forming the tiger iron. About 2000 million years ago, when a supercontinent (all the continents had come together) started breaking up, the silica layers dissolved, leaving behind just the iron stone.
Marra Mamba has beautiful color variations and tight chatoyance.