Grabbed some photos (ELissa tiara on the top there) without flash and with flash. Without is much closer to the real colour than with:
I mean I’d prefer it like it is with the flash… but hey, interference green pigment? I have and here it is tested on the top of the sequins (on the right):
As the sequins are matte this is more likely to work than had I got shiny sequins as I doubt I’d find exactly what I want in terms of colour. Also the low sheen is subtle, it makes the fabric look like 1930s real metal lame.