Gather Un'Goro Slime Samples from any of the slimes in Un'Goro Crater. Then, using the Testing Equipment next to Chemist Fuely in Undercity, see which of your samples are the most pure. Bring 5 of the Pure Un'Goro Samples you find to Chemist Fuely.
Have you heard of the Un'Goro Crater, [player]? It is near the Tanaris desert, and it is a magnificent place: lush, vibrant, full of creatures and plant life.
It is there you must go. Word has reached me that the place seems completely untainted by outside hands. Explorers are just now discovering its secrets.
I would like to test the slimes or oozes there. If it is true--that they are uncorrupt--then I would like to see how such creatures have evolved.