Renovation of outside staircase

We are having our outside staircase renovated - at the moment it is all in rather rough concrete which is crumbling. Out builder has sent us details of the work this involves. I can understand most of it, but am having trouble with the following.- Ornie per coronamento pianerottolo, pedate di gradini in pietra tipo “Gorgoglione” dello spessore cm. 5;- Lavorazione a cornice delle coste con toro sul coronamento e gradinata in pietra;Could anyone enlighten me? I would be very grateful.Karen