Geschichte: It seems as if Mallorca's coasts have always been a rich habitat for sea urchins. Meanwhile you need to be careful to not step on one. When climbing out of the water, you can discover petrified sea urchins of different sizes. They obviously grew much larger in the past.
Geologie: Sea urchins exist since about 450 million year. However, their shape changed over time. This travel stone is a fragment of a fossil sea urchin which has lived many million years ago. After its death, it got burried by mud and thereby preserved up until today.