The limestone rocks where the Caves of Campanet are located belong to the Mesozoic geological era and are about 200 million years old, having fractured and folded when the continental plates of Africa and Europe collided about 15 million years ago. The excavation of the caves by the action of underground water must have begun at least 4 or 5 million years ago. This process was possible due to the calcareous nature of the rocks and the acidic character of the rainwater with the participation of carbon dioxide present in the atmosphere and the vegetal soil. As the water filtered through it dissolved the limestone rocks on one hand and, on the other hand, created crystalline deposits (stalactites, stalagmites, etc.) at a very variable speed dependent upon climatic factors.

White is the predominant colour in the crystalline formations of the Caves of Campanet. The different chemical elements present in the water which percolates into the cave cause the other colour variations. The reds and browns are due to the presence of iron oxide or impurities incorporated in the crystalline structures of the deposits. The blacker shades are attributed to manganese.

These caves are home to a rich cave-dwelling fauna both terrestrial and aquatic that includes the beetle Henrotius jordai and the dipluran insect Homojapyx espanoli, both species endemic of Mallorca.