There is a difference between advertised 'Commonly Dropped', ie Gold/Arrows/Scrolls, 'Questing': End reward, static drop, and grind. Right now Khyber shards is a grind at 200-700 per drop, 1 in 10 chest (if that much). I hear you need 10 median size soul gem for the crafting? That's 10,000 shards = 500-200 chest needs to be looted.