Assertion: borax's boron | /r/HasProperty | brown powder
Facets:
Source sentences:
text: Amorphous boron is a brown powder.
text: Amorphous boron is a brown powder.
text: Several allotropes of boron exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard (about 9.5 on the Mohs scale), and a poor electrical conductor at room temperature.