I have been thinking about this for a while Alejandro. And, on balance, I suspect that the necklace by Cartier in your post is not the same as the one in the photos of Mrs Claude Leigh.

It is very difficult to be sure, but my impression (for what it is worth) is that there are larger spaces between the ruby motifs in Mrs Claude Leigh's necklace than the Cartier jewel. But I could be very wrong, especially as the photos of Mrs Claude Leigh are not very clear. What a pity that there aren't high definition photos of Mrs Claude Leigh wearing the necklace!