Look at the white glass here -- it's kinda seedy. If we were looking at a WV swirl, I'd be thinking "Cairo Novelty". I'm not seeing anything here which suggests "veneering" to me.
I googled ... and may see the photo you're referring to. So basically I need more input about transparent ribbons on Whities ... but also, to me, this marble doesn't look right for Vitro in the white glass either.
Need some Whities pictures!