Figure 3
From: Genesis and influencing factors of the colour of chrysoprase
Relationship between colour parameters and transition-metal elements. (a) There is a highly positive correlation between Ni content and chroma. (b) With increasing Cr content, the lightness and hue angle exhibit downward trends. (c) Both Cr and Fe affect the hue angle; the higher the content of Cr and Fe, the smaller the hue angle.
