Fans wishing to farm Purecrystal can only do so during Master Rank quests and Expeditions in the Flooded Forest. To collect the crystal, they need to go to the white and blue mining outcrops that are scattered throughout the area (via IGN). The drop rate for Purecrystal is pretty low, so players will likely have to spend some time farming several of the outcrops to get the crystals they need. You have a better chance of finding it in the white outcrops than the blue ones. This is because the white mining outcrops seem to have a higher drop rate for master rank ores. Two of the white outcrops are inside the large temple on the east side of the map, one is in the center of the map, another is a bit northwest, and the last one is in the far north near the large pool. Some of the blue outcrops are easy to collect as they are close to the white ones. There’s a lot of climbing involved, but their proximity to each other makes it easy for the player to figure out a way to mine each location as they travel through the region.
As an added bonus, the Flooded Forest is a great place to farm ore for money, so it’s a good use of the player’s time even if they don’t need all of the materials they find here in their quest for Pure Crystal.