Another tip: Sneak on it and use heavy attack with porcupine. This opening shot can deal up to 600 dmg. Then wait, parry and heavy attack again. The second heavy attack can deal up to 350 dmg.
Thats two shot kill of the stone golem who has 800 hp.
Theoretically you can land two heavy attacks without parrying, but its difficult as the second one will not hit staggered golem and will deal max 200 dmg.