Runes have no function on their own, other than beautifying your inventory. They are only useful once they're [[socket]]ed into a skill, where they alter the skill's function and often improve it. However runic alterations may make a skill less suitable to a particular use. The Wizard's skill 'Ray of Frost,' for instance, produces a straight beam that deals damage and slows enemies instantly at any range when un-runed, but produces a swirling, 360-degree field of sleet in the Wizard's immediate vicinity when under the effect of an Indigo rune, or deals less damage but has a greater slowing effect when under the effect of an Obsidian rune.

Prior to Blizzcon 2010, the Runestones (which had different names at the time) were generally accepted to do the following:

<blue><font color="#FFFFFF">Will the increase in rank continue the change that the first rank made to the skill? For example, with the WD blow dart skill, the alabaster runes turn the dart into a snake. What does a higher ranking alabaster rune do?</font>

<b>Bashiok:</b> Yes, the mechanic stays the same for the rune type in all ranks (more or less). It simply increases in power. For the Alabaster-in-Poison Dart example I’m actually not sure the increase in effect, but it likely plays off of the stun effect (higher ranks stun the target for longer). Runes that reduce cost reduce even more cost as the rank increases. A rune that would cause multiple projectiles would fire even more projectiles as the rank increases, etc. It’s not necessarily a hard and fast rule though that the increase must only be one thing. Maybe it means more projectiles AND ups the damage a little to make sure it remains competitive with other runes or skills. It has to be a somewhat fluid system.</blue>

==Runestone Scarcity==