£0.00View All
(0) Shopping Cart
Currency
FORTHCOMING EVENTS

​​​​​​​​​​​​​​​​​​​​​​​​
​​​​​​​For details of forthcoming events please click on the 'Shows & Fairs' tab above.​​​​​

​​​​​​​​​​​​​​
​​​​​​​​​​​​​​​​
​​​​​​

​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

BANDED IRONSTONE FORMATION - 2.2 billion years old - South Africa

« back
Home > MINERALS > DECORATIVE STONES FOR HOME OR OFFICE

​​​​​​​
BANDED IRONSTONE
Cut and polished slice

2.2 billion years old

Postmasburg District, Northern Cape, South Africa

 
A good example of the Banded Ironstone Formation from South Africa.

Banded ironstone provides unique evidence of the early history of life on Earth. It was formed under the sea by iron reacting with oxygen to form iron oxide (rust). This rock therefore provides the first evidence of oxygen appearing in the Earth's atmosphere, the oxygen being produced by rapidly increasing numbers of primitive, single celled algae - the only life forms at that time. These algae were for the first time using sunlight as a source of energy and producing oxygen as a by-product.
 
Banded ironstone is also an important iron ore. This example has been subjected to heat and pressure (metamorphosed) which has produced bands of magnetite, hematite and jasper.

Click on a picture for a larger image


Size:  18 x 11 x 0.8 centimetres
Weight:  430 grams

 
Optional metal stand (£1)

PRICE: £58.00
Sorry, this item has been sold or is out of stock