A collection is a series of combined artifacts. When a collection is full you can turn them in at a NPC in Meridian/Sanctum for a reward.[1]

Rewards[ | ]

[Lucky Coin]
A Sack of Assorted Rewards such as Planar Essences

Types[ | ]

In the game interface there are actually five types of collections (listed below), but only the artifact collections are turned in for rewards.

References[ | ]

  1. Collections thread on the official forums -