We've known that Diablo 3 would be bringing back runestones for a while now, but now Blizzard have posted a new update over on the official website explaining just how these mystical artifacts will function in the game this time around.

There are five runestone types: Crimson, Indigo, Obsidian, Golden, and Alabaster. Each runestone affects skills differently. For example, adding a Crimson Runestone to a skill may enhance its damage, while adding an Alabaster Runestone might add a stun effect.

In addition to their color, runestones also come in different ranks of power; the higher a runestone’s rank, the more dramatic its effect on the skill. Experiment, and discover which skill and runestone combination best suits your personal playstyle.

Swing by blizzard.com for a full rundown, including several video examples of the buffs in action.

Diablo 3 is still hopeful for (but not committed to) a late 2011 release, exclusive to PC.