Mourningwood (4 Silver Keys)
In the area where you fire the mortar, check the upper right section for a portion that you can blow away by shooting a barrel. Once you do, you can access this key.
You may have spotted this key from the Mourningwood settlement, but unfortunately you can only reach it by going the long way ‘round, through the trenches. Stick to the left while doing so and you’ll come across this key just beyond a treasure chest.
(The Ossuary) You must have first completed “Bored to Death” and “Gone But Not Forgotten” before you have access to the Ossuary. Once you enter the area, turn left, climb the stairs, then vault down to the area with the silver key.
(The Ossuary) When you enter the Ossuary, one of the tombs on the right will be open.
Shifting Sands (5 Silver Keys, 1 Gold Key)
If you hug the wall to your right as you come from the entrance to Sandfall Palace, you’ll inevitably see this key. You’ll have passed a flower and a gnome along the way.
If you’re coming from the Auroran half of the area into the Shadelight half (the halves are separated by that giant arch you pass under) immediately turn left and hug the wall to find this key.
Not far from the entrance to Shadelight, you’ll notice this structure sticking out of the sand in the middle of the desert. Underneath lies a silver key.
(Sandfall Palace) Before you reach the steps, you’ll notice a big locked door on your left. You can open this if you shoot the flit switch high up as pictured. Once inside grab the key.
(Sandfall Palace) To the left of the pedestal from which you took the legendary diamond.
(Crossroads of Passing) Once you’ve beaten the game, find the man near the tattooist in Aurora who has the Ancient Key for sale (aka the “Key to a Greater Key” quest). Purchase it to unlock the crossroads of passing, which is that door at the northwestern portion of the Shifting Sands that you may have noticed before. Once inside, solve the puzzle to reach the gold key.
Silverpines (2 Silver Keys)
Coming from Millfields, you’ll eventually reach this area of the path. Take the fork to the left and follow the trail up to the silver key.
Inside the mine at the center of the settlement.
Sunset House (2 Silver Keys)
To the left of the Sunset House Demon Door.
If you exit the golden door and turn right, you can wrap around the path uphill to find this silver key not too far away.
The Veiled Path (2 Silver Keys, 1 Gold Key)
At the end of the Veiled Path, on your right near a green flower.
(The Enigma) Inside the third room, right in the middle.
(The Enigma) You’ll need to step on the colored circular platforms in an order identical to the colored flames you see in front of you (from left to right). If you’re really lazy, the combination is yellow, blue, yellow, red, blue, red, blue, red.
Nov 2, 2010