Arghil's Dimensional Doorknob

This odd and powerful item was first crafted by the wizard Arghil during his study into interdimensional travel. It appears to be a simple hexagonal brass knob with a unique sigil on the handle and six small gemstones (diamond, topaz, ruby, opal, sapphire and emerald) set around the rose.

The doorknob is linked to an extradimensional space, as though created by the demiplane spell. Upon attunement, the extradimensional space is created, and unlike demiplane, the doorknob can link only to this one such space. The created space can be reached via the Demiplane spell if its caster knows the nature and contents of the demiplane.

While attuned, the wielder may place the doorknob against a solid, flat vertical surface with a space at least 3' wide and 6' high. Over the course of one minute, the doorknob can create a semi-permanent extradimensional doorway on the surface. This doorway can be used to travel either to the wielder's demiplane or another doorway made by this doorknob. The doorknob can create six doorways this way, and when each is created, they are linked to one of the gemstones set in the rose of the doorknob. To attune a new door, the wielder may spend a minute concentrating on the doorknob to sever one of the existing doorways; doing so frees the doorknob to link to a newly created doorway using the now unlinked gemstone color. Doors created in this way are invisible to any creature that does not know of the door's existence and exact location.

Using an action with the doorknob, the wielder may instead create a one-way doorway on the surface leading either to the demiplane or a previously linked semi-permanent doorway. This doorway disappears as soon as the wielder passes through it.

Creatures that know of the existence and exact location of one of these doors can see it when nearby. Using a gemstone door handle of the same shape as the Dimensional Doorknob, a creature may trace on the door the sigil on the Dimensional Doorknob's handle to pass through to the door, exiting from the doorway linked to the same type of gem as the gemstone handle used. If a creature has been to the Doorknob's demiplane, they can access it from one of the doors using a simple hexagonal brass doorknob. They may return from the demiplane through the door they entered from, or another door if they have the appropriate gemstone doorknob.

The surface on which the doorway is made can move so long as it remains intact (for example, you may cast it on the wall of a large wagon or over an existing door on a ship). If the surface is ever broken, the link to the doorknob is immediately severed and the doorway can no longer be passed through.

If all existing doorways are destroyed while the wielder is in their demiplane, the wielder may smash the doorknob to escape. Doing so destroys the doorknob and instantly teleports the wielder and all objects inside to random and different points on the material plane.