PSA: Archaeology summons can be looted by everyone in group
The summons from the Jar of Ashes (and I assume the boss version as well) can be looted from everyone in the group. So if you want lots of fragments, you and your friends should save them up and then use them together. 5 people with 20 each = 100 kills for each person (and approx 10-15 fragments each, assuming they all summon instead of giving AP)