Princess Margaret was wearing the Royal Victorian Chain, which is unrelated to the Royal Victorian Order.
Since royal ladies don't generally observe collar days (of which today, Easter Sunday, is one) we probably won't see the Duchess of Cornwall wearing the collar. However, HRH will now have a sash to wear at gala events, as seen below on the Countess of Wessex at the Swedish Royal Wedding.
on April 8, 2012, 10:55 pm, in reply to "