These specimens are labeled as corundum sapphire and ruby. They show a dual range of tones, between red to blue and purple, depending on the incident light and even within the same crystal. They have a very good quality and brilliance that makes them stand out from other of the same species. Crystals, which are doubly terminated, show the hexagonal prism, more or less elongated, and flattened pinacoidal terminal faces, sometimes with echeloned rhombohedral faces. On some faces we can observe geometric striated lines. They are disposed on a matrix of brilliant mica (muscovite) and feldspar.