Minotaur Horn #6 – The Olympian Citadel
After the battles with the 3 large monsters with the spiked maces in front of the great door. Just keep heading left and you will find this chest right beside a Red Orb chest in plain view.
Phoenix Feather #6 – The Muse Chamber
When you come upon the room with the music controls there are two heat vents. The one to the leftmost closest platform has a feather chest.
Gorgon Eye #9 – The Forum
After you turn the crank and move the flame a door is opened with some archers to greet you. Take them out and everything in the hallway after them. You will see gold dust at the bottom of the long spiral staircase right near the save altar. Helios’ head will reveal it.
Hercules’ Shoulder Gaurd – Below the Forum
After defeating Hercules pickup his shoulder guard. You can find it just below his body if you dive to the bottom.
Minotaur Horn #7 – Poseidon’s Chamber
After you flip the switch and open the other watery chamber near Hercules body you will swin up through a portal. Move toward the camera to reveal a horn chest next to a Red Orb chest.
Poseidon’s Conch Shell – Poseidon’s Chamber
After you meet up with the topless princess and she runs through the Hyperion gate, have a look around. You can find the conch shell to the right of the gate.
Gorgon Eye #10 – Poseidon’s Chamber
Just a little below the conch shell is a chest with another eye in it.
Phoenix Feather #7 – Poseidon’s Chamber
After speaking with Pandora’s statue and being interrupted by Zeus turn to your right. Shine the light of Helios upon the gold dust to reveal this chest.
Minotaur Horn #8 – Aphrodite’s Chamber
To the right of the top of the stairs. The chest is in the corner in plain view.
Aphrodite’s Garter – Aphrodite’s Chamber
Stick to the left side of the room and double jump and glide behind the bed. Its a bit tricky but the garter is back there.
Phoenix Feather #8 – Tartarus
Just after the viewing point of Tartarus you will see a chest on the right. Inside is a feather.
Gorgon Eye #11 – Gates of Tisiphone
Once you have pulled all four blocks to be able to access the centerpiece, make your way to the top right. There is a small balcony with a Red Orb chest as well as an eye chest.
Phoenix Feather #9 – Tartarus
After you open the Gates of Tisiphone you will see a save altar ahead, the chest is just across from it on the left.
Hephaestus’ Ring – The Forge
After Hephaestus tries to trick you, you can find his ring over near the small pool to the left.
Minotaur Horn #9 – The Upper Gardens
This is the ballista and portal puzzle. The first thing you do is turn the ballista 90 degrees to the left and fire. Hop on the rope and make your way through a few portals until you get to a Red Orb chest. Bars block your way so use the opening on that platform. Double jump and glide your way back toward the rope and you should grab it. Continue along the rope and drop down when you reach the end for another horn chest as well as a Red Orb chest.
Gorgon Eye #12 – The Upper Gardens
Now leave the ballista alone and flip the lever over to the right side of the room near the entrance. That will raise the platform the ballista is on. Fire off the missle and follow the rope to the end where you find the eye chest.
Daedalus’ Schematics & Phoenix Feather #10 – The Upper Gardens
These are suspended from the ceiling in the same room. Basically you point the ballista back in its original position with the platform raised. Fire the missile and you will breakdown the gate revealing the exit. Before you leave you will want to Hermes run up the wall to the right. Flip the lever and go back through the portal. Fire the ballista once more and the missile will break the chain suspending the chests.
Minotaur Horn #10 – The Upper Gardens
Just after the previous room and down the pole. When you land on the ground backtrack a little bit. Previously out of view is the horn and Red Orb chests.
Hera’s Chalice – Olympus Gardens
You can see where Hera throws the chalice in the cut scenes. If you miss this one it’s out of pure laziness. If you missed the cutscene you will find the chalice just a little left of the save altar. When you approach it you will have no choice but to pick it up.