The Homestone can be used to instantly teleport yourself to your chosen hometown, wherever you are. It can be used once every 60 minutes.
In the beginning the Homestone is attuned to Eldevin City, later you can re-tune it to teleport you to other cities, like Roshaven, Illaneska and Mythos. To do this you have to find and talk to the city's Homestone Marshal. To re-tune it back to Eldevin City, talk to Guide Ornan in the Central Square.
You receive the Homestone as a reward upon completing the quest  Eldevin Walking Tour.