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Lot 907* - A207 Out of This World - Monday, 04. December 2023, 04.00 PM


2.5 billion years
55 × 303 × 4 cm
190 kg
Mineral Information: Silicon dioxide (silicates) in combination with red jasper and hematite (oxides and hydroxides)
Chemical Composition: SiO2 with Fe2O3
Color: Golden yellow, brick red and metallic grey
Hardness: 5 to 7 (Mohs)
Specific Gravity: 2.64 - 2.71
Refractive Index: 1.544 - 3.22

What at first glance, due to its complex iridescent colours, appears to be a modern work of art, upon closer inspection turns out to be a anenormous slab of tiger iron. This gemstone is a special combination of minerals that occurs only in western Australia. The layered, non-transparent sedimentary rock consists of red jasper, hematite and tiger eye.

During a so-called metamorphosis, the tiger iron is formed from the above-mentioned rocks, which have a high quartz or limonite (brown iron ore) content. Due to pressure as well as movements in the earth's crust, these fold over each other and form a beautiful, visible structure. Tiger iron’s special name comes from this mixture of quartz containing tiger eye and iron–laden gemstones.

The intricate curves and waves of the layers bear witness to the immense pressures to which the rock was subjected over the millenniums. Formed in the early Proterozoic, about 2.5 billion years ago, this sedimentary rock was most likely stromatolitic in origin, i.e. a biogenic sedimentary rock, and could contain hints of the earliest forms of life on Earth. With a length of over 3 metres, this specimen is probably one of the largest and most impressive stones of its kind and can thus be understood as an extraordinary work of art by Mother Nature.

To see this Object in a Video, click here 

CHF 95 000 / 200 000 | (€ 97 940 / 206 190)

Sold for CHF 112 500 (including buyer’s premium)
All information is subject to change.