Biography
Míriel married Finwë sometime during the Noontide of Valinor and they lived in Tirion. In YT 1169, Míriel bore a son, called Curufinwë, whom she called Fëanáro ("Spirit of Fire"). After giving birth to him she could no longer live, and so wished to die, something which was impossible because, as an Elf, she was immortal within Arda.
In YT 1170, she laid down in his gardens, and her fëa peacefully departed from her body. Upon entering the Halls of Mandos, she freely lost her will to continue living in the mortal world. Her body was tended by the maidens of Estë and remained preserved. Her death was seen as a shocking event by the Valar; it eventually led to the second marriage of Finwë, and from there to the Rebellion of the Ñoldor and First Kinslaying.
After Finwë was killed, Míriel was granted permission to return to life, and she entered the service of Vairë. Her task to weave all the deeds of the House of Finwë in the Tapestry of Time.
Character
Míriel was described to have silver hair and a slender figure. Her customary singing while working was described as "soft and sweet".
Etymology
Míriel means "Jewel-woman" or perhaps "Jewel-daughter", and her amilessë Þerindë means "Broideress". Serindë was a later version of her name after changes in the language of the Noldor. However, she requested that her kin continue to call her Þerindë (Þ is pronounced "th" so therindë ).
In other versions
In other versions of the legendarium, Míriel refused rebirth.