User blog comment:VedranTheII/Pretentious Diaries 2: What tricks would you teach your Aura?/@comment-26512661-20150718155058/@comment-9464517-20150718234738

You guys are forgetting that Ruby's account might not necessarily be accurate. She only got a brief glimpse at Cinder's weaponry (given how much both were moving around), so it is entirely possible that she made an error in reporting the material nature of the objects in question.