"Man, I followed him around for days!"
Okay, I should have asked "What ULTIMATELY became of the Silmaril that Beren and Luthien took from the crown of Morgoth?"
Earendil wears it on his brow as he sails his ship across the sky; it's the Morning Star.
It became the Star of Eärendil, The Morning and Evening Star. I still like "the dog ate my Silmaril" story.