Here is the journal, translated for you to read on your own.  The crux of it says dwarves hid the ruby, the troggs hid the topaz, and a trogg named Grimlok has the sapphire.$B$BLook - you're going to need a power source to make the necklace work again.  Dran Droffers doesn't know this.  To find one, here's what I'd do: go as deep as you can in Uldaman and kill whatever construct there is the strongest.  No doubt whatever that is would have it.$B$BWhen you have everything collected, come back here!