Emerald is one of four gemstones introduced in the May 20, 2016 Tradelands update. It shares similar properties to its other gem counterparts: Amethyst, Ruby, and Sapphire (Unconfirmed). Emeralds, like the other gems, can only be obtained by striking loose rocks on Perth, Fenwick, and Freeport with a Golden or Gemstone Pickaxe. Because of these requirements, Emeralds and the other gemstones are considered to be quite difficult to get, as their natural drop rates are quite low and locked behind tools made of the rarest materials in the game.
When used to create tools, weapons, and cannons, Emeralds give them a green colored, smooth and translucent textured appearance to whatever part is affected. Emeralds have a similar durability and lifespan of Gold tools, but offer slightly higher rare drop rates.
If you mine during a storm, the drop rate of all gems is much higher than not during a storm. You may get emeralds multiple times in a row. All the way from 1 to 4.
Gem equipment has a 1/4 chance of losing durability upon use.