Anita's probably right, but I'm wondering if those spots and edges weren't created with a bit of acrylic paint - spatter for the dots and painted edges. Then we're just looking at the natural clay, finished to the level she chooses. I don't think anyone knows what she does, but her's a tutorial from someone who has come close: http://patamosaic.canalblog.com/archives/2015/04/15/31893743.html The gist is that she used pastels over raw black clay and then some alcohol on top. I use pastels to good effect over white; I've never tried over black - now I'm going to. The alcohol must be for blending. I've never tried that either.
I really wonder, looking at her necklaces, if these pieces can be as thin as they look, or if they're build on top of copper. I can't believe those jump rings wouldn't tear right through.