Is it Mecca powder? I compared my best painted polymer clay piece with one where I used silver eye-shadow and the latter looked much better. I know there's mecca powder in some eye-shadows. I love your use of metallic, jewellery, glass and texture.
Mica sounds more like it. My google insisted on Mecca and I got up some links saying Mecca was used in make-up...um..maybe my dictionary has gone wild.