They look great. The ones at Salute were pretty similar, iirc. I'm going to buy myself some more fimo.
Did you paint the symbols on, or did you do them in fimo? Nice basing, btw, is hat etched brass?
The color symbols is just different colored fimo. pretty easy- I'm no fimo expert. I just cut the symbol into the fimo and pushed some 'strings' of other-color fimo into the cut, then push it back together. I went with blue & red as pretty universal colors for safe & danger, since the symbols are kind of similar in shape and to make it easy for people playing that don't know the system already. one set in light and one set in dark stones in case they get mixed up in casting, still easy to see who's are who's.
I've used etched brass before and like it, but I haven't used any on my Twilight minis. I used some seed pods of different types from my back yard for plants and branch bits. and cork, real rocks & making rock from green stuff/miliput mix.