Zoomable Una Map, it is just a single map made of of 4096 images. Google maps works like this, and is just made of trillions of small images.
There is water on the islands, lakes and what you might call rivers. The fish may have evolved to survive outside of the water at least for some amount of time (like the lungfish), but would move from island to island. Some smaller islands could be jumped between salmon style. Some islands have blue gemin cores and just have alot of moisture in and around them or spill a rivers worth of water into the sky. Animal would have to adapt to this threat among others.
Islands do collide. Some islands attract one another (romantically), and become close through "social" means. Islands grow slowly (I mean millions of years), and larger islands can "merge" to become masses, or crystallize together to form a landmass that breaks apart when the gemin move (apart from the wind moving them). Large gemin are not "powerful" they are just contain alot of energy.
I have this excerpt to reference from my "Guide to Gemin Grading".
You can read more about gemin grading here.The Carat [ct] weight of a gemin is not very important. It determines the maximum capacity of magical force the stone can carry, but not the strength of that magical force. It is the capacity of the battery, not the voltage. Larger stones are less common than smaller ones, so larger stones tend to be more valuable. Stones are graded by size their smallest diameter, a good indicator of their maximum potential power output. Generally, gemin work more efficiently when spherical in shape.
Unlike size, color intensity is the greatest indicator of the maximum power output of a gemin. The saturation or vibrancy of the color, and its ability to radiate light a measured in a dark room or box with a polarizing filter. It is graded on a couple total criteria that will class the gemin.
It took approximately 300 hours, I have been doing this over months as there is alot of lore I have to write as well.