Originally Posted by casualcryptic
It shouldnt be a neck slot item unless its a reliquary holy symbol
It's one of those C. Champ "Special Holy Symbols" which is a masterwork item and provides a +1 caster level bonus (this one for necromancy/Undeath domain) and +1 to rebuking damage. I do love the idea that it's a tiny bit of ectoplasm in a vial.
The text implies that it could take up one hand, but also says that it can be worn and brandished when needed. So I had the idea that she would keep it on a cord around her neck, like an important piece of jewelry. Glasssteel, crystal, and crysteel all come to mind for improving the hardness. It's supposed to be made of rare materials and hard to break, anyway.
EDIT: DM ninja action!
Originally Posted by Aeryr
It is a surprisingly strong glass probably some sort of volcanic glass and magically induced. You can wear it on string around your neck. If you want you can make the two items stack into one, but I don't think it should take a neck slot, you just need to held it to use it though.