13.3" Marra Mamba Tigers Eye - Mt. Brockman (2.7 Billion Years)

This is a beautiful 13.3" polished slab of 2.7 billion year old Marra Mamba Tigers Eye From Mt. Brockman in Western Australia. One side has been cut and polished to a mirror-like finish.

This specimen includes a gibson display stand.

Marra Mamba Tiger's Eye is a rare type of Tiger's Eye found only in the Hamersley Ranges of Western Australia. Only two deposits have ever produced “true” Marra Mamba, a rare type with reds, blues, yellows, golds and greens.

Marra Mamba Tiger's Eye formed around 2.7 billion years ago when stromatolites and other photosynthetic bacteria gave off oxygen as a waste product. This oxygen built up in the atmosphere and dissolved in the sea water. When iron, produced mainly from huge submarine volcanoes, came in contact with this oxygen, it precipitated as iron oxide in the sea floor and resulted in iron-rich and silica-rich bands, which are now referred to as banded iron formations. These iron bands are often magnetic!

Geological movement over millions of years caused folding and faulting to occur, distortion the layers. Heated fluids passed through the rock and dissolved material and redeposited it elsewhere. Crocidolite, the fibrous form of riebeckite interspersed with the iron bands, was replaced by silica with fine dusts of yellow goethite and other iron-rich minerals. These fibrous bands create the chatoyant effect that gives tiger's eye its classification as a chatoyant gemstone.

Causes of Color Banding:

  • White - Quartz

  • Yellow - Goethite

  • Red - Hematite

  • Blue - Riebeckite (unreplaced by silica)

  • Green - A mixture of blue Riebeckite and yellow goethite

  • Black -Hematite and Magnetite
  • SOLD
    Tiger's Eye
    Mt. Brockman, Western Australia
    13.3 x 10.1, .6" thick