A few Gems are pretty easy to understand. Taeguk and Bane of the Trapped are a couple of examples - very easy to understand how they work and what they do. But most Gems are really vague in details of how the work or don’t work.
A good example is Mirinae Starweaver. I have no clue what smite is or does. What does it mean that below 25 you have a 15% chance to smite, but once you reach 25 you will smite enemies every 3 seconds. Does that mean smite now procs every 3 seconds ignoring the 15% chance stat below 25?