Wynncraft uses emeralds as a currency for most shops(villagers). They can be found in loot chests containing about 1-10 depending on the level of the area, or dropped commonly by any mobs about 1-2. You can store them much easier at a "Emeralds Merchant" to combine 64 emeralds to a Block of Emerald. You can compress them further into "Liquid Emerald" with 64 emerald blocks, or 64x64 emeralds. Only the richest players can get these.