Polarization phase curves of binary mixtures. The two mineral components are mixed with mass ratios shown in different colors. The endmembers of the mixture are plotted in purple and red. The mass ratios of the two components mixed together (1:0, 9:1, 4:1, 7:3, 1:1, 1:3, and 0:1) are equivalent to 100–0%, 90–10%, 80–20%, 70–30%, 50–50%, 25–75%, and 0–100% of the total mass being first and second endmember. The shaded areas around the curves denote the standard deviation, which in this figure is often smaller than the line width.