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.

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

You need these for drake saddles

Just use a doedicurus, it gets so much red gems

Abeeration coords 40 68 in blue zone there is a cluster

You can use a dodicirus or ankylo I play on lost island and i play with primal fear so if you do to then i recommend that u put the dino ur farming gems with on wandering then u pick it up with an argy and then let the dino farm the gems then when u have enough gems go back home then turn wandering off that's how I harvest gems