User blog comment:Maki Kuronami/Lesson 23: Cinder and her flames of eternity/@comment-173.63.194.85-20140912045938/@comment-67.1.153.180-20140912060805

Pretty sure its glass like her shoes; even her mask was glass (notice how it was cracked as the guards walked by it) That explains how she could hide and transform her weapon: just re-shape the glass