And so far, we have discovered that each new colour is, in fact, new, and not really the same as any other colour they have made, but we still check!
This season's two new crystal colours are: Dark Moss Green and Crystal Lilac Shadow. Lilac Shadow is an "effect" - which means that it is a coating (like Crystal AB, Crystal Copper, Silver Shadow, etc.). There may be, in the future, this coating applied to other colours, possibly as a special request, but for now, it comes on the plain, uncoloured crystal - hence the name "Crystal Lilac Shadow."
Dark Moss Green
At first glance, this looks like it might be similar to Fern Green, to me. When asked, Malliga thought it might be similar to Green Turmaline. Turns out, we are both right - it appears to be half-way between the two. Emerald, for comparison, is waaaay more blue.
In the centre front is the new Dark Moss Green, and from the left at the back is Green Turmaline, Emerald, and the relatively new Fern Green.
Crystal Lilac Shadow
Likewise, I wondered how Crystal Lilac Shadow was different from Amethyst AB. It is quite a bit different, and is closer to Crystal Antique Pink, but with more colours reflected. Malliga thought it resembled the Crystal Purple that we see in the Firepolish Glass.
The new Crystal Lilac Shadow is front and centre, and grouped in an arc behind, from the left, are: Light Amethyst, Crystal Antique Pink (another "newish" effect), Amethyst (a classic!), Amethyst Blend (newish also!), and Amethyst AB.
This is the Crystal Purple Firepolish that Malliga referred to.
Hope that helps you make some colour choices with regards to the new colours and what to combine them with! Looking forward to playing with these myself!