"Flight to Salvation" - "The Veil is Torn" [Campaign 4, Mission 2]

Gentlemen! I can't perform the ritual! Three mages are standing here, saying they need the Tear of Ashi! I've checked all the obelisks – the map is completely revealed, except for a small area in the center (a flower or crystal). Now I need to find the Tear of Ashi itself? What is it, and where can I find it? I've searched EVERYWHERE!