Some time ago I took a look at some general statements regarding the Elves, and also a more specific look at the interesting sons of Feanor. It's not meant to be exhaustive, but perhaps it might help.
General
Quote:
'In general the Sindar appear to have very closely resembled the Exiles, being dark-haired, strong and tall, but lithe.' JRRT Quendi And Eldar
Tolkien also published that the Eldar were dark-haired in
The Lord of the Rings (noting the golden house of Finarfin there). This would seem a general statement since other colours were seen in certain of the Eldar of course.
Quote:
'Elwe himself had indeed long and beautiful hair of silver hue, but this does not seem to have been a common feature of the Sindar, though it was found among them occasionally, especially in the nearer or remoter kin of Elwe (as in the case of C’rdan).' JRRT
The passage in
The Lord of the Rings seems to leave out the Eldarin Vanyar who were said (WJ) to be in nearly all members of the clan yellow or golden-haired. Perhaps the description there is (or could be said to be) more concerned with the Eldar of Middle-earth, considering the history of the Vanyar.
The Sons of Feanor
Maedros was said to have inherited some of the rare red-brown hair of Nerdanel's kin (
Russandol 'Copper-top')
The twins named
Amros (in the context of the Shibboleth the two younger sons were named Ambarussa/Amros) were both red-haired too. It was said the first and last of Nerdanel's children had the 'reddish hair' of her kin, and Nerdanel gave the twins both the name Ambarussa ’ for they were much alike and remained so while they lived (though at one point it was said of the elder Amros that he:
'grew darker in hair, and was more dear to his father. After childhood they [?were not to be] confused...'
Curufin was said to have resembled Feanor very much in face and was called Atarinke 'little father' 'referring to his physical likeness to Feanor...' (partial quote)
Caranthir Morifinwe was said to be black-haired like his grandfather -- but under 'mother-names'...
'he was dark (brown) haired but had the ruddy complexion of his mother'.
Celegorm: in Quenta Silmarillion (The Lost Road)
'golden was his long hair'. In the Lay he has 'gleaming hair', and his Old English name was
Cynegrim F’gerfeax ('Fair-hair'). Christopher Tolkien explains his choice to leave out the detail with respect to the published (constructed) Silmarillion
'on account of the dark hair of the Noldorin princes other than in the golden house of Finarfin..' but he remains 'Celegorm the fair'.
There's a marginal note describing that Nerdanel
'herself had brown hair and a ruddy complexion' (Vinyar Tengwar 41)
Still working on Maglor
