I got it at 86 NE solves (including all rares). In the same time I got 100 fossil fragments, and completed 7 Tol'Vir artifacts (including 2 rares). I actually got the trinket, then on my next digsite complete the Staff of Ammunae, then got a string of Tol'vir digsites which ended up giving me the Vial of the Sands recipe, so i was quite happy.