How to Obtain (applicable in 2.14 Version)[]
East from Black Citadel above the tunnel that leads to the assassins guild there is an area with satyrs and golems, dig with your pickaxe (spell to dig is in the backpack hotkey is [T] ) at the location shown on the picture below.
careful, the satyrs and golems are strong and will easily one shot you if you are undergeared or low lvl! Use invisibily potions or be fast :p