Not just being snarky but I really do think part of the reason Madeleine wears the aquamarine tiara more is because Snakey is wearing more of the RFs tiaras.
That may be so, but as a princess of the blood + a Bernadotte, she will always have precedence over her when its comes to jewelry in the Bernadotte family foundation to which the Amethysts parure belongs to, so the fact that she's wearing the Aquas actually emphasises her (higher) status because as far as we known the aquas belong to Princess Margareta so it is she who decides who can wear her jewelry and no one can 'force' her to loan it to some one...as opposed to the foundation where once the senior women have chosen what they want the rest can have their pick at what is left. So technically Sofia wore the Amethysts because Madde want them yesterday..otherwise Sofia would've had to settle for something else.
I also think that it might be the case that Margareta will leave her set to her brother on her death who might in turn gift it to his aqua eyed daughter in time...but thats just speculation on my part, or perhaps he might add it to the foundation