Ellesméra, Du Weldenvarden(The Inheritance Cycle), although i could totally see it as Lothlorien, too.
"The curved crossguard was also made of blued brightsteel, as were the four ribs that held in place the large sapphire that formed the pommel. Zar'roc and Brisingr
Inheritance cycle: four books- Eragon, Eldest, Brisingr, Inheritance. I want this bookmark!