Mosaics are NOT mixes. They are not yet considered a breed by any authority, but they have enough uniformity to be considered a breed by us regular people.
Breeders look for iridescent turquoise blue ears as the defining characteristic of a Mosaic. They should have blue skin on the body, and come with patterned feathers in a range of shades from light to dark. Eggs are cream/tinted. Straight combs.
They have fibro genes from Ayam Cemani in the mix.
Easter Eggers are blue egg laying Ameraucana mixes without fibro background. Pea Combs.
You could call a cross Easter Eggers if they have at least one blue egg gene.
My Mosaics are still young and I'm not the best photographer... so here are some pictures of real Mosaics from the breeder group.
Photo credit: Allison Duhon and Samantha Peters Hay.