that's Eskel medallion she holds, if you know what i mean(for those, who ships Triss/Geralt - you can pretend it's Geralts medallion for all I care, I just gave my point of view. I am one of those many people who thinks that Yennefer is the best and only possible life choice for our fearless monster hunter, and not just because of the books - in the game their behavior is the same. And in the meantime I love Triss for how she looks and for her transformation through the book story to the end of game, she kinda reminds me of myself. I hope this answer is satisfying enough for you all)