Here is the full list of all 18 Lost Artifacts: Soulstone achievements.
For clearing one roadblock
For restoring a statue
For constructing a building
For destroying towers
For the First Fountain
For the Second Fountain
For getting rid of the Wicked Thief
For speeding up the atlanteans
For stopping time
For restoring monks’ altars
For restoring the water wheel
For activating an altar
For speeding up construction
For defeating the Villain
For completing 5 levels with 3 stars
For completing 15 levels with 3 stars
For completing all levels with 3 stars
For collecting all trophies