(Not to be contused with Seal of Exorcism which is from Cursed MvPs)''
Seal of Excavation is a character bound seal that can be obtained by Temple Seals at a random chance.
Petra will require you to submit either 18 or 30 of these during the 2-hour Forgotten Temple quest.
Seal of Excavation is a 'special drop' and is not affected by Bubble Gum nor HE Bubble Gum.
Submitting 30 seals will reap more rewards than submitting 18 seals.