Answer: borts

AnswerCrossword Clue
BORTSImperfect diamonds.
BORTSDiamonds for abrasives.
BORTSLow quality diamonds.
bortsBORT, diamond fragments, also BORTZ
bortsimperfectly crystallized diamond or diamond fragments used as an abrasive
bortslow-quality diamond, in granular aggregate or small fragments, valuable only in crushed or powdered form, esp. for industrial use as an abrasive