The forms originated by the deposit of minerals on the walls of the caves are collectively called speleothems. The stalactites hanging from the ceiling are the most characteristic speleothems. And among the stalactites, the type generally known by the expressive name of macaroni -although this meaning is not officially registered- are likely the most beautiful.
Macaroni are stalactites shaped as a long, narrow tube about 8 mm in diameter, fistulous, cylindrical, and vertical. The walls of the macaroni are thin and delicate, and therefore fragile. The macaroni originate on the ceiling in caves and shelters that maintain a completely calm environment, without the slightest breath of air, from the very slow and constant dripping of water loaded with calcium bicarbonate as it has filtered through the rock. While the droplet of water holds from the tube tip, it loses CO2 by evaporation and lays calcium carbonate that slowly lengthens the macaroni. Over the years, decades and centuries, the process originates long macaroni of calcium carbonate that crystallizes in calcite and aragonite minerals.
The shelters with a roof of sandstone or limestone rock that one small stream may carve on one slope and jump over it in rainy season are meet sometimes the right conditions for the genesis of macaroni. Touching one macaroni and bothering its slow dripping is an attack against the geological beauty.
Apart from calcium carbonate macaroni, the most common ones, more soluble minerals can develop macaroni as well in shorter time. These are the macaroni made of gypsum (hydrated calcium sulphate), halite (sodium chloride) -see the macaroni in La Minilla, in the mountain of Salt of Cardona– and those made of hexahydrite or epsomite (hydrated magnesium sulphate) as the ones on the roof of the anti-aircraft shelter from the times of the uncivil war that is located next to the school Renaixença, in Manresa.
The images show the calcium carbonate macaroni on the sandstone roof of the La Sala shelter, near Sant Cugat del Racó (Navàs).
[photos Jordi Badia]