Crystals can be added to gear to give extra stats and have a chance of breaking when you die to monsters (or to players if you are negative karma). When hovering over a piece of gear, you can see how many (if any) crystals slots it has. For example, in the image below we can see that Grunil Armor has 2 empty crystal slots so we can add two crystals to this piece of gear. Certain crystals can ...