Dheryth's Gateway
(Alteration)

Range:  10 yards
Components:  V, S, M
Duration:  1 round + 1 round per level
Casting Time:  8
Area of Effect:  10-foot diameter disk
Saving Throw:  None

This spell creates a vertical disk 10 feet in diameter. It is a magical portal to anywhere that is on the same plane, and that the caster had been to previously. The portal clearly shows the other terrain and permits two-way travel from either end of the gate to the other. Nonliving material can only pass through if carried by a living creature.
The gateway does not automatically open to the intended spot. The success roll is dependent on distance to the target:

within 100 miles	99%
within 500 miles	50%
same planet	10%
other planet in same sphere	5%

Thus, an attempted gateway from Waterdeep to Bloodstone would open with only a 10% chance of success, while a gateway from the south shore of Nyr Dyv to Greyhawk City would be 99% likely to work.
If the gateway fails to open properly, there is a 50% chance that it opens somewhere else. The exact location can be determined randomly or at the DM's discretion, but it need not be near the target spot. It could as easily open to a place a thousand or more miles away as on another planet. In any event, the material components, a 6-inch diameter platinum mirror (200 gp or more) and a diamond-nibbed pen (used to draw the gateway in the air, 1,000 gp or more) are consumed by the casting.
The gateway can neither target nor originate from a place that is sealed from teleportation or interplanar travel (eg. areas guarded by some sort of screen, sanctum, etc, or rooms lined with gold or lead).

