Item:Soul Gem: Essence of Earth

can be obtained by casting trap the soul on a CR7 earth elemental.

Tested: CR9 - didn't work Tested: CR8 - didn't work.

There are 4 CR7 earth elementals in the Depths of Despair (on Hard).

You must use Small_Khyber_Dragonshards in the trap the soul spell for CR7 earth elementals