Dark Crystal Enhance Stones are used to improve Dark Crystal Weapons. To increase the item level of a Dark Crystal equipment, have it in your inventory along with Dark Crystal Enhance Stones. Right-click the Dark Crystal Enhance Stone and a dialog will pop up that allows you to enhance any Dark Crystal equipment in your inventory. It takes 10 Dark Crystal Enhance Stones to increase a Dark Crystal Weapons to +1, 20 for +2, .., 100 for +10.