Luster The appearance or quality of light reflected from the surface of a mineral is known as luster. Minerals that have the appearance of metals, regardless of color, are said to have a metallic luster(Figure 2.10). Some metallic minerals, such as
FIGURE 2.10 The freshly broken sample of galena(right) displays a metallic luster, while the sample on the left is tarnished and has a submetallic luster. (photo courtesy of E. J. Tarbuck)