You know who never wears her engagement ring is Marie Chantal. I think it was a unique ring but she must not like it. I never actually saw a very clear picture of it but one stone was a sapphire.
Yes, I don’t remember it as being one of my favorites. It’s an oval cabochon sapphire set sideways with a diamond to one side. I don’t tend to like “flag” rings (like this one and Marie’s).
Here’s a pic of MC’s ring:

My favorites are Princess Eugenie’s & Princess Clotilde of Savoy.

Agree, Eugenie’s ring is one of my favourites

I also really like Meghan’s, I’m a fan of all diamonds. TBH I quite like Mary’s, for a “flag” ring, the setting is very nice, and the stones are lovely. I think she ruined it my adding the extra diamonds (of course)! Much better than Marie’s fugly one! And for sheer diamond power, you can’t go past Margrethe’s whopper!