There is a whole range of raw materials and items that you can collect in Nier Replicant. Many of them will be needed for various quests, and a lot more will be needed to upgrade all of your weapons so you can earn yourself the related achievements/trophies.
One of the materials you'll need to collect is Pyrite, which can be particularly hard to find. You'll need 14 of these in total to cover all of the upgrades that require it, so we've put together a short guide on exactly where to farm this coveted material.
Where to Find Pyrite
The best place to farm Pyrite is in the Barren Temple and there is a chance of obtaining it from any of the glowing gathering spots.
This location unlocks as part of the main storyline, but you'll need to grab the Royal Compass in order to visit it any time after that. Depending on when you visit the Barren Temple, you might need to complete some of the puzzle rooms again, but they do not involve any blocks in Part Two and simply require you to defeat shades while obeying the rules.
Additionally, you can unlock more of the Barren Temple in Part Two by completing the quest "Disturbing the Sleep of Kings", giving you more places to search for gathering spots.
Leaving the temple and re-entering will cause gathering spots to respawn, so you can farm through the temple once more and then rinse and repeat until you have all the pyrite that you need.
Note: There is also a chance of obtaining Pyrite from the crates within the Junk Heap, but we found the Barren Temple to be the best farming spot.