Classic WotLK, old world quest:
It shows that "Sand Skitterer"s ( https://www.wowhead.com/wotlk/npc=11738/sand-skitterer#drops;q=earth )
are dropping "Elemental Earth" ( https://www.wowhead.com/wotlk/item=7067/elemental-earth )
but wowhead doesn't show it on their loot table and I just farmed for over half an hour without any luck.

Related Quest: Shaman quest "Elemental Mastery" https://www.wowhead.com/wotlk/quest=8410/elemental-mastery

Questie v7.5.2 & WoW WotLK Classic 3.4.1 (48632)