Well it's been about 3 months since I started some other tests with the silicone and tiles. It's obvious now that something is leaching off the silicone and into the tile. I simply removed the silicone donut from the center of the tile I had it sitting on, and I think it's plain as day what has happened.
It didn't even take water to see that the tile was ruined.
I put a few drops of water spaced out from the center on out, and you can see how hydrophobic the tile is where the silicone soaked into it.
After about 30 minutes.
Here's what really has me confused. The tile I had stuck inside cured silicone caulking seems to have absorbed something as well. This picture was taken 30 minutes after setting the tile in a small puddle of water.
You can see the clean tile on the right is completely saturated with water, while the one has no water absorption past the point where the tile was stuck in the cured silicone.
I assumed this was caused by some chemical leaching from the addition curing silicone, but apparently not. It seems like it's any silicone.
This means I need to keep these tiles in these silicone donuts for as little time as possible, and the jig I had planned for making these formicariums in bulk will need to be made with a completely different material. That's going to make this thing much more difficult to make. I need something that will create a seal around the tile, but won't ruin it.