The Case of the Funky Flakes

[CCoburn]

Fairly straight forward explanation here.

When water freezes it will eventually 'freeze out' or extract the minerals from the water.  What you are seeing is just the minerals in solid form after they have come out of solution.  Because it is a lot more difficult for the minerals to dissolve back into solution they remain in a solid state, and this is what you are seeing.  As a general rule, the minerals are good for you, and your body needs them.

Sometimes water can be "too pure".

Edit -- What you are probably also seeing is a higher concentration of the minerals due to the minerals collecting on the ice trays over numerous freezing cycles.  Same principle, just a higher density.  It's highly unlikely that the particles you see are tiny pieces of the ice tray itself.

The water is a bit on the 'hard' side here, but I also eliminated the water hardness factor by resorting to RO and distilled, so mineral accumulation and transference may have been a dynamic at one time, and I'm not sure exactly what that would look like, but this is pristine H2O we're talking about, so I don't think what I was seeing was any type of residual or composite mineral 'contamination' especially given the amount of time that had passed since using any type of water containing any minerals.