HOLLOW IRONSTONE CONCRETION - Surrey

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HOLLOW IRONSTONE CONCRETION

Upper Greensand

Redhill, Surrey

In sandstones iron is usually present in the groundwater and it is often deposited as hard, insoluble layers of iron oxide. Odd-shaped concretions are sometimes formed consisting of concentric layers of iron minerals such as limonite and goethite.

Some concretions are hollow and filled with loose sand. These were probably formed when the iron originally cementing the sand grains was dissolved and drawn to the outside, forming this curious iron oxide ‘shell’.

This is a very good example. One for the collector of unusual works of nature!

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Size: 12 x 9 x 8 centimetres
Weight: 414 grams