What are "Rare" and "Unique" urethane eyes?

Rare colors could be considered to be "mutations" or variants of a normal color. For example, perhaps the color for some reason turned out brighter or darker than a normal eye. This creates "happy accident" special variant eyes. Rare eyes are not flawed eyes. They are normal Grade A eyes. Please see the individual description to understand what makes an eye Rare.

Unique colors are usually OOAK eyes that I will only make once. Sometimes I make them as an experiment, or for a special event.

What's the difference? Rare colors will pop up from time to time naturally, by mistake or accident. Unique colors are usually specifically created to be different and special on purpose. 

Rare colors are usually a by-product of Order Periods. For example: if someone ordered Tie Dye eyes, but they came out with a strange pattern on the iris, or the color looking too light, then I can't send them to the customer. So I make a new pair for the customer, and sell the "weird" color later as a Rare color.