Solarian Truesteel

Mined on the fourth layer of the Seven Mounting Heavens of Celestia, this fine iron needs no alloy and shines with a silvery gleam. When forged into a weapon, it gives the wielder a +1 bonus on the confirmation roll for a critical hit.
Solarian truesteel has 25 hp per inch of thickness and hardness 11.
Price: The market price modifier for such a weapon is +1,000 gp.

Source: Book of Exalted Deeds