Fragments (Subnautica)
Fragments are items that result in usable Blueprints once analysed by the Fragment Analyzer.
As such, fragments are the first item required to create high-technology items. They take up one inventory slot. Once analysed, a Fragment of a certain type does not yield any new blueprints when analyzed again.
Note: Currently, all fragments appear as white safes in the game world and most of them appear as "?" marks in the inventory.
Future
In the future Fragments will only be found in and near wrecks. Several Fragments will be needed to unlock a blueprint and Fragments that are no longer needed will be convertible into Titanium. The fragment analyzer will be removed and the PDA will be used to scan Fragments[1].
Lore
Fragments were once whole usable items but were heavily damaged and distributed over the map during the crash landing.