Here is the full list of all 20 Aquamarine achievements.
Installed first pod module
Harvested first plant
Experienced first vision
Released creature in Coral Woods
Discovered secret area in Coral Woods
Opened doorway in Drowned Harbor
Discovered secret area in Drowned Harbor
Crafted all camp upgrades
Experienced first dream
Cooked first food item
Scanned all lifeforms
Crafted all pod modules
Experienced all dreams
Reached exit in Hidden Subterrane
Chose to stay with Seekers (Ending A)
Chose to return to home world (Ending B)
Gave food to a creature
Filled garden with symbiotic plants
Dropped & recovered a gem
Starved without going underwater