Bort

Noun

bort

(plural borts)

(uncountable) Poor quality diamond, used for industrial cutting or abrasion; a poorly crystallized diamond.

1931, Bloomberg Businessweek, Issues 82-94, borts%22&dq=%22bort|borts%22&hl=en&ei=9QpXTpaZEMrkiAL51pXFCQ&sa=X&oi=book_result&ct=result&resnum=3&ved=0CDEQ6AEwAjge page 25,Bits that would require 4 to 16 carbonadoes are now set with 40 to 80 borts.