Astral Block

Area 
No spirit or insubstantial being may cross an astral block’s boundaries for the duration of the spell. In addition, insubstantial creatures within an astral block cannot become substantial, and vice versa. Thus, a sorcerer could not cast Ethereal Body (VH) within the area of a spell, while a ghost would be unable to use Solidify. A ghost already in a tangible state could not become insubstantial!

Duration: 10 minutes. 
Cost: 4 to cast and 2 to maintain if cast as an Area spell. 15 per cubic yard if cast on a container, and half that to maintain. 
Time to cast: 2 seconds. 
Prerequisites: Summon Spirit and Repel Spirits.

Item 
(a) Wand, staff, or jewelry. Usable only by mages.
Energy cost to create: 600.  
(b) Any area or container may be permanently enchanted for 100 times casting cost.  
(c) A container of any size (from a stoppered bottle to a starship) may be enchanted for an energy cost of 500 per cubic yard or fraction thereof. 
The container must be at least airtight when fully closed. This creates a mobile astral block. Any spirit coaxed into the enclosure (or in it when the spell is cast) will be affected by the spell when it is closed. Opening the container temporarily suspends the spell.