Gems can be bought by themselves in the Chamber of Commerce, and there is also a great chance to reward gems in daily activities. Two gems of the same type and grade can be combined into the next grade, and a high-grade gem can also be decomposed into two gems of the previous grade. The higher the level, the stronger the effect.
All kinds of gems have different functions, and each has its own set of parts, so it can be set according to the ability requirements of its own profession and the characteristics of each equipment.