This quest is not available in game.
Marvon Rivetseeker in Tanaris wants you to collect 30 Gahz'ridian Ornaments.
<name>, I'm a scientist, but also a treasure hunter at heart!
Long ago, when trolls used to occupy this land, they created large amounts of ornaments modeled after Gahz'rilla, a hydra they worshipped as a deity. These ornaments are carved out of an element that I call "Gahz'ridian," after the hydra god.
I did find some myself, but I'd like to have some more to study -- maybe you can find some?
I even invented a detector that makes finding the Gahz'ridian a snap! Just put it on, and the search begins!