How can you get all the three symboles in Virtual Villagers 3?

The pink diamond is the easiest one just do alchemy and do rose+cactus+lotus have one of your villagers drink it and place them under the pink gem in the orchid, you have found 1 key.

Next, you must fix the statue and reshape the blue orb then you must have your tribal chief take it and give it to the pearl. You have found the 2nd key

This final key can only be done with TIME there is no way to force it. Now this may be hard or easy for you, drag your villager to the waterfall if he just gets a drink you can't get it yet. If he grabs a bowl and puts the fire out. It's time(dramatic voice) don't stop him! once the fire is out you will see a diamond let the diamond cool or let your villager grab MORE water

This should help you a lot! :)