The glowing message

As you focus on the message, the symbols shift into English letters. It's a riddle of some sort. You notice that for the first time, all six gems are glowing. The riddle reads:

Ivory isn't here today.
She and Jade went to play.
Violet went on a vacation.
Scarlett's giving presentations.
Amber's off to work again.
So who's left to let you in?