From Diablo Wiki
If you are trying to farm for the item then it's easiest to select the Siegerbreaker (Start Quest) quest from the Quest Selection screen. This will give you The Bridge of Korsikk Waypoint which is always at the very bottom of the Fields of Slaughter.
Once you have located the Caverns of Frost, head to level 2 and find the Superunique Lacuni, Chiltara. He has a chance to drop the Gibbering Gemstone. There is no guarantee that he will spawn but when he does he will drop the Gibbering Gemstone.
The Gemstone is Account Bound so it can not be traded for.
Chatty Gem You feel like talking to someone.
 Other Reagents Required
Players must assemble the five ingredients and the Staff of Herding plan to enter the level.
- Black Mushroom ( )-- Found rarely in a room on Cathedral level one, in early Act One.
- Leoric's Shinbone ( )-- Found rarely in the fireplace in Leoric's Manor, in late Act One.
- (Leoric's Shinbone is *not* present or required in the Diablo 3 console.)
- To farm for this select Quest number 9 "The Imprisoned Angel" in the Change Quest menu when you log in. Take the Waypoint to Leoric's Manor. You will have two rooms to fight from the back of the manor to reach the room with the fireplace in.
- Wirt's Bell ( )-- An Act II vendor (Squirt) sells it for 100,000 gold on her Potions and Dyes tab.
- Liquid Rainbow ( )-- Spawns in the Mysterious Cave in the Mysterious Chest in the Oasis, Act 2. Save Zaven the Alchemist and he will open the entrance to the cave. The chest is located on level one.
- (Liquid Rainbow is *not* present or required in the Diablo 3 console.)
- Gibbering Gemstone (Chiltara in the Caverns of Frost, Level 2, Act 3. It’s in the Fields of Slaughter. If you get Ice Caverns exit out try again. Chiltara is a Superunique with a low spawn chance. )-- Random drop from
- Plan: Staff of Herding ( )-- To teach the recipe to Haedrig. Drops randomly from Izual, Act 4.
Once the Staff is created, it can be upgraded to the Nightmarish Staff of Herding, Hellish Staff of Herding, or Infernal Staff of Herding via Gorell the Quartermaster, an NPC merchant found in the town section of Bastion's Keep.
Map of Fields of Slaughter
|Items of Diablo III  Item Basics Normal Items Legendary Armor I Legendary Armor II Legendary Weapons 1h Legendary Weapons 2h Item Sets|
|Item Basics||Item Modifiers||Inventory||Artisans||Merchants||Miscellaneous |
|Armor - Class-Specific||Weapons - Class-Specific||Crafting Items||Other Items |
|| • Blacksmith Plans
|Waist||Wrists & Hands||Legs & Feet||Head |
|| Voodoo Masks - WD|
| Chest Armor
|| Amulets cont.
|| Rings cont.
40) Puzzle Ring
|| Sources - Wiz|
|| Fist Weapons - Monk
|| Mighty Weapons - Barb|
|| Daibos - Monk
|| Bows |
|Item Sets |