Lúthien Tinúviel, the fairest of the Children of Ilúvatar. Daughter of Elu Thingol (an Elf) and Melian (a Maia) it is said that when she was born "...the white flowers ofniphredil came forth to greet her as stars from the earth." (The Silmarillion, J.R.R. Tolkien).
I think Tolkien can best describe her... "Blue was her raiment as the unclouded heaven, but her eyes were grey as the starlit evening; her mantle was sewn with golden flowers, but her hair was dark as the shadows of twilight. As the light upon the leaves of trees, as the voice of clear waters, as the stars above the mists of the world, such was her glory and her loveliness; and in her face was a shining light." (The Silmarillion, Chapter XIX - Of Beren and Lúthien)