D&Dtools1

You rub the gem over the target, causing an image of the target to gradually materialize in the depths of the gem.
As you complete the arcane gestures of the spell, the image becomes perfectly clear and then vanishes, leaving no trace of the spell on either the gem or the target.
Powerful true dragons of all varieties commonly employ this spell.
When the spell is cast, you create a permanent link between the focus and an object.
Anyone who holds the focus can sense the target of the spell as the spell locate object, but with unlimited distance, as a standard action.
In addition, anyone who holds the focus can scry the bearer of the object, as the scrying spell, as a standard action.
The bearer of the object is entitled to a Will save, but is treated as if familiar to you and as if you possessed a lock of his hair.
Focus: A gem worth at least 100 gp.
Origin: According to draconic legend, gem tracer was created by the first dragon whose hoard was plundered.