The Portal Mastery skill is a class skill that the Caster profession starts with. It allows you to craft magical portalstones that are bound to a specific location or place on a map. These portalstones can then be used to create temporary portals that last for a few minutes and let anyone on the current tile access the place the portal is bound to.
Skill Use
The creation of portalstones requires the use of the World > Make Portal screen. The Make Portal screen provides a map of the immediate area you can move the displayed area by clicking the white arrow buttons in the bottom middle of the screen.
If you wish to make a portalstone that is bound to another realm you will need to use World > World to travel to that realm and then use the Make Portal screen.
To make a portalstone, click on one of the tiles and it will update the right side of the screen giving you an indicator of how much portal mastery skill is required and if you have enough skill. You can confirm the creation of a portalstone by clicking on the listed tile on the right of the screen, this will then add the portalstone to your Inventory > Queue screen.
Formula
Skill Required = (Tile Level * 5)
i.e. To make a portal to a level 5 tile you need 25 portal mastery skill (5 * 5).
Making a portalstone will reward you with a guaranteed skill gain right away and experience once your trade queue completes.
Possible Uses of Portalstones
The primary use for portalstones is to create a one-directional clickable portal to another place, these are temporary but anyone can use a portal once activated for however long it lasts.
The secondary use is for the creation of permanent portals, these can be inserted into portal rooms inside buildings and it may also be possible to place a fixed portal on an owned tile providing quick access to another place.