Artisan's World - Stone Hill Key

If you are 171/200 Gems on the Stone Hill level like I was and wondering how to open the metal chest in the basement with the lock on it - this tip is for you! At the end of the Stone Hill level right next to the teleporter, shown in my screen shot above, you'll find those sparkly lights that you can jump into that float you upwards. Jump over the side next to the sparkly lights to find a hidden beach.

Follow the path down, collecting the gems until you find the golden key. Then of course head back to the chest to open it with this key and that should get you the rest of the gems you need for this level! If you're still missing some - they're probably from the fields along the upper portion of the level or around the castle which separates the fields.