Assertion: boron's form | /r/HasProperty | crystalline
Facets:
Source sentences:
text: The pure form of boron is black and crystalline, and extremely brittle.
text: The amorphous form of boron nitride (a-BN) is non-crystalline, lacking any long-distance regularity in the arrangement of its atoms.
text: All other forms of boron nitride are crystalline.