fulvous / tawny
  Reddish-yellow, dull yellowish-brown.

flavescent & xantho-     Yellow
festucine                Yellow

ianthine, adj.
  Violet

tourmaline & rosy-blue

niveous
    Snowy, resembling snow; white and lustrous like snow. Also in extended use.
    https://www.oed.com/view/Entry/127420