The in-game description of the Orb of Osuvox states that it can generate a spherical shield around itself that is impenetrable and indestructible. Nothing magical, scientific, man-made, or technology-based can destroy the shield other than the avatar using the Artifact.
The Orb is used by IOI to shield Castle Anorak from outside gunter interference and ensure IOI's exclusive access to the Third Gate. Parzival manages to hack into IOI's data requisition system and detonate a bomb near the avatar using the Orb. The shield becomes deactivated, and in the ensuing chaos of the Battle of Castle Anorak, IOI loses the ability to reactivate the Orb.
The current location of the Orb is unknown; it was presumably lost after the detonation of the Cataclyst.
A Level 99 Mage is required to keep both hands on the Orb to activate, and retain activation of, the Orb of Osuvox. So long as these conditions are met, a indestructible shield with a radius of half a kilometer will cloak the user and anything around him/her. The shield also penetrates the ground underneath the user, and encloses everything inside the shield.
While the shield is active, nothing can enter or exit the confines of the shield. This means that any avatar using the Orb should take precautions for long-term stays inside the shield until their task is complete. IOI brought varying degrees of weaponry and the majority of their army into the shield before engaging it. Additionally, the avatar using the shield must keep both hands on the orb at all times; this makes long-term usage of the shield ineffective, seeing as an avatar would need to eat, sleep, and bathe. IOI negates this issue by passing control of the avatar in question to other people, allowing multiple people to control the same avatar and, thus, keep the Orb of Osuvox active indefinitely.