This is unbelievably sad. Of course, we know the story, tragic for both Elves and Dwarves, but there is something particularly moving that your protagonist seemed unemotional. And yet, the last paragraph packs a punch in the gut.

And I thought, all of that grief and death because a bunch of demigods couldn't keep their mouth shut, only they had to demand the Silmarils. They should've known better.

Greatly done!

Oh man, yes there are always two sides to everything and everyone loses in the end in a war. :( 

The friendship between the children makes this even sadder.

This was very moving, all the more so because your character is (now) so far removed from it. The individual fates of the "supporting cast" of the Silmarillion can be just as heart-breaking as the big events, and your story illustrates this perfectly.

This is tragic and lovely. (Is that weird to say?) I like it.

Oh, ouch. This packed quite a lot into such a short piece. An interesting argument for Thingol to make, that the Silmaril was owed to him for the life of his kin, and one that left him very open to the dwarves' claim of the Nauglamir. And of course, the human fallout...