Clay is a particularly surprising rock. Soft and fragile when dry, it is malleable when in contact with water and can...

Almost unbreakable, this rock constitutes much of the crust of our continents and the root of our mountains. This roc...

There’s a rock that crystallizes the beauty of the world more than any other. It’s sandstone. This rock, rich of the ...

There’s a peculiarly young rock at the scale of geological times. It comes from the bowels of the Earth and is born f...

This rock is recognizable by its white color; the great builders have chosen it for their most edifying monuments. Bu...