Hold and use the item a blood orb.
To obtain this item you need to get a dowsing stick from An incensed water weird located in Desert Of Thorn. The stick is now bind-on-take, and level 185. And the blood orb will be bound to the same person as the stick. So the mark is not doable if you're lower than level 180.
Simply go outside with the stick, hold and use it. The blood orb will pop in the same room where you used the stick.
For magically finding the location of a blood orb, the Powers have granted thee a Mark. You have been granted the Mark of Divination! You gain 99,000 experience points! You gain 65 practices!