Assertion: tin's form | /r/HasProperty | powdery
Facets:
Source sentences:
text: Tin exists in two different forms, or allotropes: the familiar form, white (or beta) tin, and gray (or alpha) tin, which is powdery and of little use.
text: The other form, gray tin or alpha tin, is powdery, about two thirds as dense, and appears spontaneously at low temperatures.