GemCraft, the online sensation played over 90 million times, has arrived!
Experience a completely new chapter in the GemCraft series featuring an all new user interface, stunning retina art, and levels designed specifically for mobile gaming.

The goal in GemCraft is to combine the magic powers of 8 gem types each with its own special abilities. You can use Pure gems, or combine gems together to craft new and powerful multi-color gems with both their strengths.

Use gems in towers and traps to wipe out hordes of monsters preventing them from reaching your mana crystal.

GemCraft features:
-Completely redone beautiful hand-drawn retina graphics
-32 levels across 4 worlds
-Detailed skill system with 27 unlockable skills
-Combine 8 types of gems together to form hundreds of combinations
-Game Center achievements and scoreboards
-7 different game modes
-3 difficulty levels to engage both beginners and experts
-Unique XP system that challenges you to beat your own best scores

Source: http://itunes.apple.com/us/app/gemcraft/id418510736?mt=8