Hexolite Quartz can only be found on Feybreak Island in the latest update of Palworld: Feybreak. While you don't need any advanced tools to mine this fairly abundant resource, you do need to be ready for a high-level fight.
Warning: Mining Hexolite Quartz is Dangerous!
There are two main hazards to mining this resource on FeyBreak Island:
Feybreak Warriors (level 50+) — Once you're on the island, they will attack you on the ground or shoot down your flying Pal mount.
Pals (level 50+) — Nearly all Pals on the island are hostile to you.
If you have a fast pal mount you can outrun most of these encounters, but make sure you're careful otherwise this could be a one way trip.