Secrets of the Elven Shrine - Act 1 Side Quest
Location: Elven Shrine
Closest Portal: Elven Shrine
Objective: Collect Lost Sapphire of the Elves & solve the Elven Shrine puzzle
Reward: Outrider's Signet + Gold/Loot
Secrets of the Elven Shrine is a Side Quest in Act 1 which begins by speaking with Leanne, an NPC in Eirulan found above the Pet Shop. Alternatively, if you uncover the hidden room inside of the Elven Shrine you'll begin the quest that way too. For this quest you will need to track down the Lost Sapphire of the Elves and return it to Leanne.
You can find the entrance to the Elven Shrine in the Western Greilyn Jungle, you'll have to visit this location during The Plague Primary Quest. A screenshot of where you can find the entrance of the Elven Shrine is shown below.
Once inside of the Elven Shrine you'll find the entrance to the Secret Room next to the elevator that takes you down into the heart of the shrine. There will be a button on the wall which you need to press that will uncover a hidden door. Use my screenshots below if you'd like to see exactly where this secret room is as well as the location of the button that opens it.
If you would like to see a video of me completing this quest check out my Secrets of the Elven Shrine Quest Walkthrough. Once you uncover the Secret Room all you need to do is complete the block puzzle to reach the Lost Sapphire of Elves. This block puzzle is common throughout Dungeon Siege 2, how it works is there are piles of certain colored blocks (or orbs in this case).
Mouse over each pile of blocks and it'll tell you what color it is, you will need to pick up each colored block and place them into the correct socket that matches the color. Doing this will unlock a lever which will allow you to travel to the next floor. You will need to find more buttons on each floor that will open up hidden rooms but aside from that it's just a simple block puzzle.
I recommend you pick up 2 blocks per pile so you don't have to back track later to pick up more.
You'll find the Lost Sapphire of the Elves that you need at the very end of this puzzle. Return the item to Leanne in Eirulan and you'll receive some items along with the Outrider's Signet unique Ring. The quest will complete when you speak with Leanne.