Here is the full list of all 6 Stones of Solace achievements. It takes around 0-1 hour to unlock all of the achievements on Windows.
Meet the Sunken Nymphea, Eidolon of Peace
All idols discovered
Meet the Baleen Fossil, Sanctuary of Memories
Meet the Millenary Cat, Herald of Eternity
Meet the Claymore, Paragon of Trust
Meet the Empty Hands, Essence of Intimacy