Assertion: crystalline boron | /r/HasProperty | 99% pure
Facets:
Source sentences:
text: In 1997 crystalline boron (99% pure) cost about $ 5 g and amorphous boron cost about $2 per g.
text: In 1997 crystalline boron (99% pure) cost about US$5 per gram and amorphous boron cost about US$2 per gram.