The Losacio Stone: Uses and Exploitation of a Historical Resource (Zamora, NW Spain)

Abstract The area around Losacio (Zamora) is known for the existence of antimony, silver, lead and tin mineralization, having existed in the past several mining works for its benefit, associated to the presence of an intrusive body (called Losacio Granite) that generated an aureole of thermal metamorphism with abundant centimetric chiastolite crystals. However, the presence of these andalusite prisms in the metasediments that constitute the hostrock of this granite (Santa Eufemia Formation) also aroused interest in past centuries because of their durability and the strange aspect they present —in the form of a “hen’s foot”— when, after a certain time, the weathering leaves the andalusite crystals in relief. From the review of documentary sources, we have established the different uses for which this variety of stone was exploited, as well as its different facies that condition them. All this is based on in-situ observations, petrographic studies and the location of the main mining areas of this unique stone, to which the planning and strategies used for its exploitation give even more particularity. This research underscores the historical importance of the Losacio stone, its radius of influence from the mining area to the place of use, and the singularities of its transport. For all these reasons, the historical quarries associated with this variety of stone are vestiges of extraction that should be protected, preserved and disseminated.