A lot of us reach for a traditional pearl necklace when we want something classic or conservative, but a necklace made with clear beads or stones can work just as well. Clear stones/beads go with any color outfit and are a little more original and unexpected. Crystal/glass, white topaz, rock crystal or lucite necklaces can be found in varying price points for any budget. One of my favorites is this rock crystal necklace from Verdura:
Verdura Rock Crystal necklace
Stones or beads that are rounded, and not faceted, work especially well for daytime and the office.