During this time Fëanor creates his Masterwork, the Silmarils, in which he captures the light of the Trees. Varda imbued the rings "so that thereafter no mortal flesh, nor hands unclean, nor anything of evil might touch them," (which leaves me wondering how the Silmarils and the quasi-mortal half-Elves would interact) and Mandows foretold that the very fates of Middle Earth lay within them.
I'm going to assume no one here is surprised that Melkor wants them for himself? I actually find Melkor's desire and frustration regarding the Silmarils backing for his claims about teaching Fëanor being little more than lies. He could make many great and terrible things, but these lay beyond his power. That being said, there's nothing to say how much knowledge from Melkor made its way indirectly to Fëanor. What cannot be denied, however, is how skilled and insidious were Melkor's lies. He spoke to them of favoritism, of ambition, and glory. And, it cannot be denied, Melkor is good at subversion.
Fëanor is called to account for aggression triggered by his own ambition and poisoning by rumor. While this reveals Melkor's influence, Fëanor is not held blameless for his action and is banished, creating a fulfillment of Melkor's words. With his heart tied to the Silmarils and the pain of his banishment, leaves Fëanor ripe for temptation. Melkor tries, but incites such wrath that even he experiences fear, slinking away to lick his wounds and bide his time.
The light of the Two Trees still shines, but now the Valar wait uneasily for the fragile peace to shatter again. The next Chapter is "Of the Darkening of Valinor," so I think we know that shattering comes soon.