Let's play!

I had this idea in the shower this morning. It's a silly game/puzzle for my readers.

I am a magic color sorting box. You name a color (or colour, if you prefer), and I will sort it into one of two piles, using a simple rule or rules. Your challenge is to figure out what rule(s) I am using.

Restrictions: Each of you may only name one color per post, after which you have to wait until I have responded before posting another.

You may guess what the rule(s) are at anytime.

First, I drop two into the magic color sorter to get the piles started:

Initial piles:

red

green

Those are the two piles. I will edit this post to update the piles as the game goes on.

Current piles:

red vermillion blue brown black chartreuse lavender saffron

green purple beige yellow orange periwinkle pink magenta turquoise gold pumpkin

Good luck!

Puzzle answer.

If you have given up on this post's game, you can find the solution within the cut text.

( Spoiler answer for the puzzle below )