Calle de la Pizarra
The street takes its name from slate, the blue-grey stone that roofed the Madrid of the Habsburgs.
Slate is a fine-grained metamorphic rock, dark and split into flat sheets that come away cleanly. That quality made it a roofing material: nail the overlapping slabs and the water slides off. Madrid took it up in the sixteenth century, when Philip II brought from Flanders the fashion for steep spires, and the silhouette of slate towers and pinnacles came to define the skyline of Habsburg Madrid.
The origin of the word itself is uncertain: it has been linked to Basque and to Latin, without proof.
Why this name was chosen for this particular street in the Imperial district has not survived in the records. Calle de la Pizarra is a short stretch in the strip of Arganzuela near the Manzanares, and its sign joins the names of nature and materials in the Madrid street map.