Vetro's Dark Violet seem very similar to the Moretti New Dark Violet of a few years ago. Slightly streaky, nice soft plummy colour. It does reduce slightly to a slightly brassy lustre. This can be reduced with a soak in CLR (see front bead in picture to the left. (After being CLR'ed, vs the one's behind) Same beads below, before treating.)
This brassy reduction could be used to good advantage, and is easy enough to get rid of if undesired.