This item is not available in game.
This item was the quest reward from A New Ore Sample. Both it and the quest were removed in Cataclysm.
It was a lousy quest reward for a pain-in-the-you-know-where quest. Many players back in the day just skipped it because of the sheer frustration involved in finding and killing the "correct" kobold. I myself only did it in the waning days of Wrath of the Lich King because I was finishing up my Loremaster achievements prior to Cata. (That bad, folks, that bad.)