I don't think the charge of "killing his mother" can be laid at Feanor's feet. Though I do think her death may be the result of his birth.
"Miriel was the name of his mother, who was Serinde, because of her surpassing skill in weaving and needlework; for her hands were more skilled to fineness than any hands even among the Nolder. The love of Finwe and Miriel was great and glad, for it began in the Blessed Realm in the Days of Bliss. But in the bearing of her son Miriel was consumed in spirit and body; and after his birth she yearned for release from the labor of living. And when she had named him, she said to Finwe: 'Never again shall I bear child; for strength that would have nourished the life of many has gone into Feanor." (The Silmarillion, Quenta Silmarillion, Chapter 6 - "Of Feanor and the Unchaining of Melkor", pg. 63) .
Part of what happens to Miriel can be understood in how this child gets his name. He was originally named Finwë or Finwion after his father and later Curufinwë ("Skillful son of Finwë") Feanor was a miracle of a child, but came at great price. He was burning with such a fiery spirit, that his mother gave him the name "Feanor". His name is a compromise between the Sindarin Faenor and the Quenya Fëanáro, meaning "Spirit of fire"...Such was his strength of this spirit that his mother Míriel was consumed and chose to pass on to the Halls of Awaiting with Mandos after his birth.
"The tragedy of Miriel, who in giving birth to Feanor is "consumed in spirit and body", is that she loses the desire to live... The Silmarillion gives no explanation why Miriel would lose the will to live except that she poured into Feanor strength and life enough for many children. However, Morgoth had already been at work among the Elves in Cuivienen before the Valar came, and he sowed among them seeds of despair. Miriel's loss of the will to live...even to raise her child...shows a loss of hope, perhaps resulting from Morgoth's deceits. In the drafts of an unsent letter, Tolkien makes reference to the "strange case" of Miriel, who tries to die, wishing "to abandon being, and refusing rebirth." The results of Miriel's actions, he writes, are "disastrous" and lead "to the 'Fall' of the High-elves." (Letters, 286) It is also suggested that had Finwe "endured his loss and been content with the fathering of his mighty son...a great evil might have been prevented." (Finwe remarried and had other sons...Feanor has constant strife with his two step-brothers)(Dickerson, Matthew : author "Finwe and Miriel", pages 212 - 213, J.R.R. Tolkien Encyclopedia, Scholarship and Critical Assessment, 2007 edition, Michael Drout editor)
So Feanor doesn't really kill his mother. It is the process of his birth, and perhaps some foresight in what is to come, that Miriel chooses to lay down her life voluntarily.
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Vocatus atque non vocatus, Deus aderit Called or uncalled, God is present
Bear, The quote you gave concerning Finwe and his weakness in marrying another woman is amazing. Finwe's entire little soap opera has a greater importance than the general vision the Silmarillion tells us. It is a shame that Tolkien did not delve deeper into this scenario.
Filli, I agree with you. Pregnancy and birth are difficult. A gift but very taxing. I had not even considered the Post Partum (sp) Depression aspect of Miriel's birthing experience. Excellent insight.
If I'm not wrong, pregnancy and birth were even more difficult to elves than to mortal women and required more physical and mental effort. Does anybody remember, in what text Tolkien wrote about it and whether he wrote about it at all, I wonder? =)
You might be thinking of Laws and Customs, or at least this much is said there anyway:
'Also the Eldar say that in the begetting, and still more in the bearing of children, greater share and strength of their being, in mind and in body, goes forth than in the making of mortal children.'