Specifically aura of maetanrus. I thought it was something excessive like 9 hours but seems like its falling off all the time lately without me noticing. No timer and no fade text. If I know how long it lasts I can make a gina timer though.
I think any and all auras will fade after being in the same zone for 90mins. They all refresh on zoning but if you don't zone after 90mins you will have to manually recast them.
Having to recast an aura like that is punishment for playing so conservatively that you don't die. Be more ambitious!
I use this ex: 01/12/17 11:24:13 PM Aura of Maetanrus Rk. III expires. I'm not sure a timer would work very well, it resets when you zone.