Pyrite

Pyrite may shine like gold, but it is nothing more than iron sulphide (FeS2) and it is worthless. Hence its nickname, ‘Fool’s Gold’.
The Bernissart iguanodon skeletons were completely filled with pyrite. When clay from the swamps covered the dinosaur corpses, they were decomposed by blue-green algae (cyanobacteria). The acid released reacted with the iron in the clay, thus forming pyrite. It gradually filled the many holes in the bones.
The word ‘pyrite’ is derived from the ancient Greek puritês lithos, meaning ‘fire stone’. Prehistoric man used it to make fire: striking pyrite against flint until there were sparks. The sparks caused a dry tinder fungus to glow, which set fire to dry twigs and grass.
Several specimens of pyrite are exhibited in this room, such as this aggregate of pyrite cubes.