Iridium Mod/Rarity

Rarity is a property that applies to all items, loosely indicating their value and the difficulty through which they are obtained. An item's Rarity is indicated in-game by the color of its name text, as displayed, for example, when rolling the cursor over the item in an inventory slot. An item's Rarity can be raised or lowered by up to two tiers depending on its Modifier.

The Iridium Mod adds a new rarity to the game, the Emerald.