Andrew Battagel finds a geode
Last week, Andrew Battagel enjoyed a frosty morning undertaking a contamination investigation next to an old colliery near Radstock, Somerset, not far from where he grew up. Surprisingly, a sparkling piece of gravel in one of our boreholes turned out to be a geode!
Geodes – hollow stones in which mineralisation has formed crystals growing inwards into the void space – are common in the Triassic Mercia Mudstone deposits of the Mendips, where anhydrite nodules have been replaced by minerals including quartz and calcite. In Somerset, these geodes are commonly found near Dulcote, outside Wells, and in the Avon Gorge, Bristol, where they are known as ‘potato stones’ or ‘Bristol diamonds’.
This geode is now is a nice addition to Andrew's desk-museum!