The Palacio del Cordón was built in the XVII century. Instead of the Palacio del cordón in 1575 there were situated the casas del cordón wich was the residence of Antonio Perez (the secretary of Felipe II). He carved a wooden cord in the casa del cordón because he lost in the battle of Almansa. He lived there from 1575 to 1585. Manuel de Becerra and Alberto Aguilera also lived here.
All the symmetry of the palace is centered on the stone cord at the entrance. This cord was carved by Antonio Perez one century before Antonio Pérez lived here. The stone cord was carved when the palace was built to simulate the wooden one
Why were these rocks selected
They used granite because it is a hard and though rock that resist erosion, and it was very used in Madrid at that age.
They used limestone because it was (and it is) very used in that time because it is easy to recognise, but is less hard comparating it with cooper
The alterations granite sufferes are because of living microorganisms, pollution (carbon dioxide), and meteorological phenomena such as rain(granite is not very resistant to watter), wind … etc. They cause the rock to become darker and to turn red.
limestone sufers alterations when is in contact with acid (for example hydrolic acid), it can be diluated by watter with the pass of time, and this causes the rock to be dissolve in watter.
If we compared the materials used in the Palacio de abrantes, we can see that it has granite in the columns of the door and limestone.