The following things will help you to unlock several achievements:
Flower Child: Create a flower
Tick-Tock Doc: Earn 75,000 points in timed mode
Big Cheese of the South Seas: Create a black perl cluster
Collapse Master: Earn 5,000 combos across all games
Marathon Mogul: Earn 150,000 points in Marathon mode
Hexic Addict: Play 100 games of Hexic
Millionaire Extraordinaire: Earn 1,000,000 points across all games
Oyster-meister: Create a black perl
Star Gazer: Create a cluster of bonus stars
Survivalist: Beat Survival mode
Cluster Buster: Create 25 combos
Grand Pearl Pooh-Bah: Create a black perl flower