Thingol was said to have had
'long and beautiful hair of silver hue' in
Quendi And Eldar, and his hair is described as
grey silver in
The Grey Annals.
In 'Of the Coming of the Elves' (The Later Quenta Silmarillion I) there is a description of both Olwe and Elwe concerning their hair:
'The locks of Sindo were as grey as silver... but the hair of Elwe was long and white' (name changes include Elwe > Solwe, Sindo > Elwe).
By the end of revision here, in 'Of the Coming of the Elves' as it stood in LQI, the hair of the brothers is again described, and now Olwe's hair is long and white but the hair of Elwe was grey as silver.
'The Loremasters also supposed that reference was made to the hair of the Sindar. 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 Círdan).' JRRT Q&E