[ she stops her admonishment in surprise when he reveals he does in fact know how dangerous this tool might be, and she's distracted enough by the heel-face-turn of his expression that it takes her another moment to register the second thing he says.

rey blinks quickly. it doesn't occur to her that there might be anyone else from her world here, either resistance or first order-associated, so she sees no harm in telling anything other than the truth. ]

Something similar, in concept, yes. But different in the actual design. It uses a crystal as a power source to generate the blade of energy, and it's a strong enough weapon to slice through solid metal.