The ribbon doesn't look like it dips. One has a a vague corkscrew like pattern but made up of short separate ribbons (not sure whether it's four of five (one could just be a tail of the other).The other is more of a highly distorted baseball stitch, again made up of separate ribbons that meet and it looks like it's six.
No obvious green of aventurine but there's a slight glitter to some of the black particularly along the ribbon edges.