Tint her slightly toward violet and hazy gray, don’t bring black elements all the way to black but only down to payne’s gray, maybe a bit of transparency. That and depending on what medium you’re using, you could use an iridescent white mixed with the white and instead of a mixing white for a pearly effect. Fade her colors somewhat, even russet use an iridescent russet.

And/or paint her with some translucence, so there are hints of what’s behind her coming through her, that’s a possibility. But I think iridescence might work. Especially if you use something like the Daniel Smith Interference colors. I used Interference Green as a white substitute many times – it changes hue between a near-white green and a near-white magenta depending on angle of viewer and so it has a prismatic effect when used over white or light colors.

However, it does read as darker than pure titanium white, so make sure there are no areas of pure white and that the lightest values are the strongest iridescent or interference colors. All of the Interference colors flash between complements, yellow to violet, orange to blue and so on, but they are very pale near-whites. Iridescent whites in either Daniel Smith or Winsor & Newton Pearlescent medium read as one step darker than white.

Also if you’re using pastels, the Pan Pastels have iridescent and pearlescent colors that handle the same way, and Sennelier has a good range of iridescent colors. Using those can give something a bit of a sparkle but it’s also a fairly subtle effect when they’re used in context for correct value and hue combinations. It’d look a little unearthly if everything else was painted in earth colors, earth red barn and browns and grays and olive greens and so on in the scene.

I hope this helps. Don’t know what medium you’re using but there are iridescent colors and mediums for anything I can think of.