This chapter of the Deep Rock Galactic guide has all the information about the Aquarq crystal - where to find it, how to identify, and what it can be used for.
Aquarq crystals are an additional resource necessary for completing Point Extraction missions - they appear only in these missions. These crystals are extremely well hidden throughout the underground complex. The Aquarq crystal can be obtained in several ways - with a simple pickaxe, the special Driller tool, or with explosives. Once the crystal is separated from the rock, it can be picked up.
Aquarq crystals are very large and heavy so the miner has to carry them in his hands and put them in a deposit located on the drilling platform. During transportation, the player cannot perform any additional actions (shoot, use a pickaxe, etc.) - this will cause the crystal to fall on the ground.
How to find Aquarq?
Aquarq crystals are hidden inside ice walls - you can recognize them by the blue spots on the rock surface and the slight blue glow emitted by the crystal itself. Aquarq crystals can be hidden far up so Engineer's or Scout's help is invaluable during this type of task.