I would like to think that, if Tolkien's elves had access to fountain pens, they would use them exclusively, though dip pens might be more realistic, given their time period.
This writing sample is actually from several years ago, and it was something that I found, while working on a writing sample, which will go live next Saturday!
(For any Tolkien linguists in my reader base, I would like to disclaim that there may be errors in transcription!
The Tale of Gil-Galad
Gil-galad was an Elven-king.
Of him the harpers sadly sing:
the last whose realm was fair and free
between the Mountains and the Sea.
His sword was long, his lance was keen,
his shining helm afar was seen;
the countless stars of heaven's field
were mirrored in his silver shield.
But long ago he rode away,
and where he dwelleth none can say;
for into darkness fell his star
in Mordor where the shadows are.
Pen: Speedball C-5
Ink: Winsor & Newton Crimson