Rarity

All monsters, strongboxes and most of the items come in one of four different rarities. The common rarity is, followed by ,  and. Higher rarity means things are higher valued but occur less frequently in the game.

Items
Items receive a random rarity with items being the most common and  items the least common. Rarity is rolled before base type. The game rolls for rarity, in order, starting with:, followed by , then , if none of the other rarities are rolled the item will be. Statistics impacting Item Rarity change the chance at each step.

,, and items found by the player are initially unidentified and a  must be used to discover their properties.

The number of sockets that can be found on an item is not affected by rarity; this instead relies on its item level.

Item modifiers' random values can be rerolled using a.

Normal
items (also called base items) are basic items without any explicit modifiers added by affixes. Nevertheless depending on base type some items can have implicit modifiers that can be rerolled using a if they have a range.

A item can be upgraded into a  item using an, or a  item using an. Using an can upgrade a  item into a, , or even  item of the same base type.

Magic
items have the same base statistics as a item of the same type, but have magical modifiers on them given by affixes, up to one prefix and one suffix. The types of modifiers that can be found or added to an item depend on its item level, the base type and any additional flags on the item (such as shaped or elder).

A item with only either a prefix or suffix property can have a second property of the missing type added to it by using an. The affixes can be rerolled with an.

A item can be upgraded into a  item using a. It will retain its current affixes and one new affix will be added.

When is equipped, it grants player dropped  item identified.

Rare
items function the same as items, except they have at most six affixes – up to three prefixes and up to three suffixes. Found items or items made  with an  or an  will always have at least 4 affixes, but it is possible to get a  item with only 2 or 3 by using a  or. A item with less than 6 affixes can gain an additional mod with an  or through Master crafting. completely reroll a item's affixes, again giving between 4 and 6 mods.

items are given a randomly generated name.

Jewels and Abyss Jewels can only have up to 4 explicit modifiers; Maps can have 8 mods as a result of corruption.

Unique
have the same base stats as a item of the same type, but have specific names, unique artwork and set lists of modifiers instead of affixes. While the three preceding rarities are strictly better than the one before (e.g. items are always more powerful than  items), this is not the case with  items. They usually provide different and particular modifiers (sometimes thematically grouped) that can't be found on other items. Therefore they are considered to be more build-defining, granting effects that can be built around, but generally grant less pure stats than items.

It is GGG's intention that each base item has at least one corresponding item.

Increased Item Rarity/Quantity
Players can boost their chances of getting powerful equipment and uniques with the statistics and. The combination of rarity and quantity stats is sometimes called Magic Find or MF, referring to the equivalent stats in Diablo.

Rarity and quantity stats can come from player’s equipment, the support gems and, monster rarity, party bonuses, and map bonuses. The stats on the character stack additively with each other, and are subject to diminishing returns. Stats from the party bonus and monsters stack additively with each other, and are not subject to diminishing returns. The total player bonus stacks multiplicatively with the total party & monster bonus. (An explanation of additive vs. multiplicative can be found here.)

IIR and IIQ from gear do not affect chests, and have no effect on the number or type of currency, items, scrolls, or gems that drop from them.

Increased Item Rarity (IIR)
Increases the chances of an item being, , or. This statistic has no effect on the number or type of currency items, scrolls, or gems that drop since they have no rarity like, , or. ,, and monsters have an inherent increased item rarity statistic for drops.

When in a party, only the statistics from the player who lands the killing blow on an enemy is applied - multiple characters attacking a monster will not stack their item rarity bonuses together. If one of your minions gets a kill, the minion's IIR is added to yours and the total is used.

Theoretical Maximum Increased Item Rarity
1 Two Andvarius are equipped for 170% IIR. 2 Triple corruption mod with a perfect roll. 3 The Item Rarity Support is level 20 with 23% quality for a total of 70.5% IIR 4 The rare gear consists of a 50% IIR helmet. If legacy gear is used a legacy Brinerot signature 30% IIR while using a flask pair of gloves that also have 32% IIR can be equipped. In total this provides 12% additional IIR over the non-legacy version. 5 To get the IIR from the ascetic along with all other unique and rare IIR bonuses the player needs to have a normal weapon equipped. 6 The player needs to be on low life.

A player can also equip jewels which provide 4%-6% Rarity of Items Found per jewel, resulting in up to 126% additional Rarity(if using all 21 sockets found on the passive tree)

Increased Item Quantity (IIQ)
Increases the average number of items that drop from monsters (aka Drop Rate). This includes currency, scrolls, skill gems and divination cards. There is no cap on the usefulness of this statistic, since there is no limit to the number of items a monster can drop. Only the IIQ of the containing area and the party bonus affects chests or strongboxes, and it does not affect the type, quality, or rarity of item dropped, only the chance that something will drop. A player's IIQ does not affect the amount of maps that drop from enemies. However, a map's IIQ does affect the amount of map drops.

In a party, each player in the party after the first gives the equivalent of +50% item quantity statistic on currency and gem drops along with a statistic of +10% item quantity and +40% item rarity on other drops (this also doesn't affect map drops). The base chance for an item to drop varies between monster types, and drop rate increases with monster rarity. The party bonus as well as any bonus the monster gives are additive with each other and multiply with the quantity bonus of the player who gets the killing blow.

Theoretical Maximum Increased Item Quantity
1 See Bisco's Collar page for 22.5% IIQ explanation. 2 For non-legacy gear an IIQ corruption can be put on the amulet but not the rings since they would lose their socket implicits. For legacy gear IIQ corruptions can be put on the rings, amulet, and belt resulting in an additional 20% IIQ. 3 The Item Quantity Support is level 21 with 23% quality for a total of 45.05% IIQ. 4 Triple-implicit corruption mod, with a perfect roll. 5 The rare gear consists of 2 rare rings and a rare helmet each with 20% IIQ. A rare amulet is not used because Bisco's Collar provides an additional 2.5% IIQ.

Monsters
Higher rarity on a monster means it drops more items and is more likely to drop items of high rarity. Additionally, a character can gain more items of higher rarity by increasing the increased item rarity and increased item quantity statistics with their equipment or with certain skill gems.

Monsters of higher rarity drop items of higher item level. Magic mobs drop items one ilevel higher than the area's monster level, and rare/unique mobs' items are two ilevels higher.

Normal
The most common, and spawn in large groups.

Magic
Increased statistics, and given one monster affix. They appear in smaller groups. Magic monsters may also spawn with a Bloodlines modifier.

All magic monsters receive the following mods:

Additionally magic monsters receive a life multiplier based on their level:

Rare
Greatly increased statistics, and given three monster affixes. They spawn by themselves, but multiple rares may still be close together. Rare monsters may also spawn with a Nemesis modifier, or inside an Essence crystal.

All rare monsters receive the following mods:

Additionally rare monsters receive a life multiplier based on their level:

Unique
Custom monsters that appear in certain areas, including bosses. Some unique monsters like Tormented Spirits and Rogue Exiles can spawn in most areas as well.

All unique monsters receive the following mods:

Interactions with other mechanics
The statistics increased by monster rarity are life, damage, experience gained on death, item drop rarity and quantity, and flask charges gained on death. Monster rarity also reduces the chance to flee.