Gem Stack is a free game available on the iPhone platform developed by BYTETYPER YAZILIM TICARET ANONIM SIRKETI. In this game, you collect raw gems and stack them to create unique rings for your customers. The game is based on a simple concept, but it can quickly become addictive.

The game starts with you collecting raw gems, which you break, cut, and shine to upgrade their quality. The better the quality of the gem, the more money you can earn from selling it. However, you need to avoid obstacles that can damage the gems and reduce their value. As you progress through the game, you unlock new gems and upgrades that help you create even more valuable rings.

Overall, Gem Stack is a fun and addictive game that challenges you to create beautiful rings from raw gems while avoiding obstacles. It's a great game for anyone who enjoys casual games and wants to kill some time while having fun.