Roofing slate from the town of Bernardos can be found in most buildings erected by the Spanish monarchy from the 16^th to 19^th centuries, making it a highly important component of Spain’s architectural heritage. The quarries are located outside Bernardos, 145 km north of Madrid, in the Precambrian terrains of the Iberian Variscan Orogen. Although from a petrographic point of view this rock is in fact a phyllite, for the purposes of construction it is known as roofing slate. Bernardos phyllite has a set of specific characteristics that make it a unique rock which is clearly distinct from other roofing slates. These particular features, together with the history and singularity of the outcrops, make it an ideal candidate for Global Heritage Stone Resource (GSHR) status. Today there is no longer any convenient replacement for this stone, which makes it very important to give it the best possible recognition in order to ensure the availability of this resource in the future. This paper reviews the historical meaning and petrophysical characteristics of this rock, and proposes it be designated as a GSHR.