The Elder Scrolls VI: Alinor. That's what it reminds me of.
"A city made from glass or insect wings. A hypnotic swirl of ramparts and impossibly high towers, designed to catch the light of the sun and break it to its component colors, which lie draqed across its stones until you are thankful for nightfall."
I bet they haven't done Summerset Isles yet because they want to do it justice. I think you're right.