What's a word that describes something incredibly beautiful, that you can never own, and which might only exist for a short time?
These words come to my mind when I think about the concept I'm trying to describe: transient, ephemeral, sacrosanct, inviolable, fleeting. Something beautiful you can only see but can't own.
The broad-leaved epiphyllum is a cactus that bears flowers for only one night per year. Its blossoms might be described as _____.
I'm specifically looking for a word that has at least strong connotations of extreme beauty. The romantic idea of a beautiful rare flower that blooms only once a year, in the middle of a desert where no one will see it in the first place, is all I wanted to paint with my example.