How can you tell what tier level an epic gear is. There is nothing stated in the info.
The price helps a bit.
20 s → T1
30s → T2
50s → T3 or T3.5
70s → T4
80s → T5
1g20s → T6 (*1g50s, thx Cappa)
1g50s for t6 
There are also many epic dungeon gear that has a vendor price of 50 silver coins.
Khitai faction gear can have a vendor price of 1.2 or 1.6 gold coins
50s with critigation is dungeon gear, without t3.
You can look it up at aocisbetterthantv.de/armory.
T1-3 and t5 of a class have a uniquish look tjat only changes in color.
T3,5 t4 and t6 look unique to every class and tier.