Stoneglare Mask is an Immortals Fenyx Rising Gorgon Armor Set gear piece (Helm) you can unlock while exploring the Clashing Rocks area of the video game developed by Ubisoft. The Gorgon Armor Set Helmet or the Stoneglare Mask is in The Observatory, as you can see on my map below.
How To Unlock the Clashing Rocks Observatory Backroom Epic Chest
To get this piece of gear, go to the back of The Observatory, and you’ll find a locked room like the one pictured below.
In front of it, there are three plaques with feathers on them. Your goal is to find three stones and place them on the said plaques. The first stone is on the right side while facing the gate. Look for it in the pond and use Herakles’s Strength to pull it up and place it on one of the three plaques.
The second one is on the left side while facing the same gate. Climb the first hill and carry the stone pictured below to the second plaque.
Now, retrace your steps to the hill where you found the second stone (left side) and continue to climb until you see the third stone. As you can see is behind a building.
Carry it back to the third plaque at the back of the building. Now, the gate should open, and the Observatory Epic Chest is accessible. Head inside and collect the Gorgon Armor Helmet.