Silver Hilt

This is a part of the Silver Sword. If you have the Silver Blade then after you return to Athkatla in Chapter 6 and go to one of the major locations in the city (Waukeen's Promenade is most likely) you will run into a Githyanki named Kruin who demands that you hand over the Silver Blade. You can either give it to him or decide to fight with him and his friends. Apart from other loot he drops the Silver Hilt.

In-game description
"This is a piece of Silver Sword, a vorpal two-handed sword used by the Githyanki and considred holy by them. It is magically sharp and can sever limbs and heads with ease. If the whole weapon could be found, it could be magically reforged."