In J.R.R. Tolkien’s The Silmarillion, Fëanor creates the Silmarils.
Fëanor is one of the greatest Elven craftsmen in Tolkien’s mythology. He makes the three jewels in Valinor during the Years of the Trees, before the First Age. The Silmarils contain the light of the Two Trees of Valinor, Laurelin and Telperion, and their radiance makes them unique among the treasures of Arda.
When the Vala Morgoth destroys the Two Trees and steals the jewels, Fëanor swears an oath to recover them. His oath and the resulting rebellion of the Noldor drive much of the First Age narrative. The Silmarils eventually pass through the hands of Elves, Men, and divine powers before being lost in the earth, sea, and sky.
Celebrimbor creates the Rings of Power in the Second Age, so he is often confused with Fëanor. Aulë is a Vala associated with craftsmanship, but he does not make the Silmarils.