On astraeos map you can find red gems all the way at the bottom of the abberant cave on phokintos. Same area where rockdrakes roam

To the guy who needs red gems on the island for some reason??? : no, you cant. What in gods name do you need red gems for on THE ISLAND?

In aberration ascended, I saw and mined these in the blue zone, 40 Latitude 68.4 longtitude, you can mine it without getting irradiated

If you’re on abb I would recommend going into the Red zone and mining some. But if on genesis just go to the ocean biome and go to one of the underwater tek cubes and one of them has all 3 crystal types in it hope this helped.

You need these for drake saddles

Abb radiation zone on Valguero I think gives the most per crystal. You get red and blue gems

The bubbles in crystal isles has alot of them

If you're on Extinction lategame, use tek gloves to farm them in the Sulfer biome.