Acquiring Troilite in Subnautica 2 is important if you want to make Mangalloy Ingots, but unlike Atacamite, this material is much rarer, and there actually seems to be a rather limited amount. Many players have complained about soft-locking themselves after they processed all available Troilite into Mangalloy Ingots and were unable to get any more.
This is because even Metal Farms, devices that produce a metal of your choice, require you to insert one of said metal into them first. So, whatever you do, keep one Troilite for use in any future Metal Farm, since you're going to need a lot of it later to repair the Alien Power Plant and progress the story.
Subnautica 2 Troilite location
You can find Troilite in the glowing...
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