Hue is the color of the gem
not the purity
it goes by the colors in the rainbow
the hue 1 would be red
and the higher the hue the closer the color is to violet, so it would go to orange then yellow, then green, blue, indigo, violet and all the colors inbetween
 "Hedgehog Launch 2"){kind=icon}
 "GemCraft chapter 0"){kind=icon}