There are so many interesting views of the clasp in this video. I found some of the really interesting views impossible to capture. All that I would wish for is that the video was in colour.
From the evidence we have available to us, I believe that the three strands are all part of the Indian pearls from the Lahore Treasury. Two of the strands form one necklace joined by the clasp of two rubies.
Some stills from the video
As one of the posters on the RJWMB (probably Baxter) noted years ago, the clue to identifying the Indian pearls from a side view is the inclusion of a small pearl between each large pearl towards the back of the lower strand.