EastScape Wikibuilt from the game itself
Geode egg
“Put it in a hatchery on your island with 3 Ordinary pet food: a Crystal Crab in 72 hours. Tradable.”
Hatches
Hatches into 
Crystal Crab in your island's hatchery, in 72 hours. It drops from monsters in The Carnival, The Vault, The Wilderness, The Deep Wild, The Depths of the Mountain.
Sold by
Nestor the Egg Man in The Yard trades it for 60 abyss crystal + 2 glimmering geode.
The Store: 600,000 tickets.