Fourth Wing Question

Hi first time Fourth Wing reader. Maybe I missed it or just don't understand. Does Violet get a signet or did absorbing the power from Andarna count as a signet? I'm 60% through and her not channeling her signet is something I do not understand. Am I not far enough for this question to be answered yet cause it feels like she did get her signet but is keeping it a secret. I also remember something about Tairn can't channel. Maybe it's something I totally missed please help. Also it's fine if you have to provide a small spoiler to answer my question.