Kelen's Dagger of Escape

The stealthy rogue Kelen was well known for his ability to slip away from any pursuit and find his way out of even the most escape-proof traps. Only upon his death did the world learn that his secret was really in the glass-sheated dagger he carried. The pommels appear to be fitted with an immense ruby, but this stone si also made of glass, a fact even a poorly trained merchant can recognize.