My all time favorite is Lapis lazuli, because i love the deep blue and gold pyriet colors.
I tried to recreate a part of Elisabeth's crown ( one of them:) The little flowery bit.
Sadly that aim was too high. The flower succeeded, but the leaves to the right didn't work out.
I ended up making a kind of sceptre, embellished with sequins in lapis colors. It still looks kinda regal:)