New evidence for the Arkenstone-Silmaril case

[blantyr]

Originally Posted by Galadriel55

The Silmarili are unique from all other stones because they are unbreakable, and also because they shine with the light of the Two Trees.

I would also note that at Smaug's liar, the third time Bilbo went down the tunnel, was described as absolutely dark. Once torches were lit, the Arkenstone reflected light, but it did not glow on its own.

Is the Arkenstone ever described as giving off light on its own?