Decoration-Slate-Flooring-With-Slate-Stone

decoration-slate-flooring-with-slate-flooring-bathroom-home-improvement-28 The gold crystals are likely to be pyrites, a type of metal inclusion that is present in all natural slates, but not always visible.  Visible, stable Pyrite inclusions in a T1 rated Scottish Roofing Slate. Some pyrites may cause staining or even holing.