Dave. in answer to your question about HM's bracelet(s), she is wearing her Three Strand "Knotted" Diamond Bracelet on her right wrist and her silver Patek Philippe Ellipse watch on her left wrist.

As to your question about the colours of the dresses of the royal entourage, HM traditionally wears either white or gold for State Occasions such as the State Opening of Parliament, State Banquets and the State Diplomatic Reception.

Her Ladies-in-Waiting follow suit.

This along with the Windsor Jacket worn by men are the only real remaining relics of "court Dress" worn by the BRF.

For the State Opening of Parliament all Royal Ladies wear white. For other functions, such as banquets, the Duchess or Cornwall will also wear white but other Royal Ladies will wear coloured gowns.

HM often wears quite colourful gowns at other non-state functions