The Colours of Iron
‘The Colours of Iron' (Lochaber, Scotland) by Ursula Lawrence took the third place) in the Geological society’s 2018 Earth Science Week photography competition, 'Earth Science in our Lives.'
A micro landscape photographed on an exposed quarry face of Ballachulish Slate Formation. The dark coloured mudstones contain Iron Pyrites (Iron Sulphide). This reacts with oxygen and water to form iron oxide (rust) and sulphuric acid. The acid reacts with any calcareous cement in the mudstone to form gypsum (hydrous calcium sulphate). This reaction is very important to engineering geologists as the acid attacks concrete and the gypsum causes heave.