"Pure" means that the shown genetic trait (fur or eyes or whisker color or tail etc) is the same is the hidden genetic trait. In other words, it's about the genetics game.
There is
a thread about the genetics here. It is very difficult to breed a pure cat, and generally people only try to get a few of the traits on the cat pure so as to lock that trait into the breeding line. That
is an example of good breeding practice.
A cat with all of the Most Recessive traits on the charts is by definition pure because there are no traits that can hide underneath those traits - they can only equal each other.
All of the traits are drawn by Callie Cline and released into the breeding pool hidden in the Collection Cats. That's one reason why everyone breeds Collection Cats so fiercely - to find the newly loaded traits.
At market the newest traits are expensive when they first come out because only a few people have them. It's supply and demand. As more people breed the trait, it spreads. Cats can also get an elevated price at market if it is very well-bred to be match and beautiful - the combination is lovely and it took a lot of breeding work to create the cat. Those cats may or may not have some pure traits in them.
Cats which have multiple Most Recessive traits are often quite valuable because they are so useful as pullers for hidden traits. That goes on until the market becomes swamped with those Most Recessive traits. KittyCats releases new Most recessives into the gene pool. For instance, we have a new Most Recessive fur: the Chimera - Black Maltese Chinchilla and at this point only a handful of people have it - or fewer, 2? 3? people?
