Not just a jewel - Father's Silmaril, the most beautiful things ever created by hand of mortal being, the only remaining source of the Light that was before moon and sun, and Father's most prized creations. But I suppose if you mean, "does it have any world ending powers" then no, it does not - beyond that it is precious beyond price to my father, and holds a light that can never be dimmed and will not stand evil's touch, it is, still 'only' a jewel.

And the nature of such Oaths is binding, beyond life, beyond death - we may have no rest until it is fulfilled.

[ A light flickers in his eyes, hungry and desperate at the offer, but he shakes his head ] And embroil you in our problems? No Will, I do not want you bound to our Oath as well, and you will be, if I use your magic. And I only have two wishes left - I do not want you trapped in your bottle.