Shardestones are mythical items that allow you to teleport to different places on the server. They have a short cast time before activating and a 10 minute cooldown unless you buy the Greater stone equivalent. Shardstones and Homestones are dangerous items as they can hurt or even kill players when using them, so it is best to insure that you are at full health and in a safe location to prevent accidents.
The follow stones currently exist in the world for purchase:
Shardstone - 200 Gold - Teleports you to the Market. 10 Minute Cooldown
Greater Shardstone - 2000 Gold - Teleports you to the Market. 30 Second Cooldown.
Homestone - 500 Gold - Teleports you to the Market. 10 Minute Cooldown.
Greater Homestone - 5000 Gold - Teleports you to the Market. 30 Second Cooldown.
In the past, some other types of Shardstones existed, but they are not possible to purchase anymore as they were phased out for other ways of travelling around the city.