Emerald

Emeralds are a invaluable Item found underground and by killing many Mobs. They are most importantly used to craft Emerald Armor.

It should be noted in Crazy Craft Emerald Ore is easier to find

Use
Emeralds are used for many different things in many different Mods, but in Crazy Craft 3 and Crazy Craft 4 they are most used early game for Emerald Armor. They can however still be trades with Villager for all different kinds of loot, however, its never quite as useful in Crazy Craft. They can also be used to activate a Beacon or to make Block of Emeralds for decoration.

Mod Form
Emeralds are from Vanilla Minecraft.