silicon carbide

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A bluish-black crystalline compound, SiC, one of the hardest known substances, used as an abrasive and heat-refractory material and in single crystals as semiconductors, especially in high-temperature applications.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun chemistry A binary compound of silicon and carbon, SiC; it is one of the hardest known materials, and is used as an abrasive, under the trade name Carborundum, and as a refractory material.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun an extremely hard blue-black crystalline compound (SiC) used as an abrasive and a heat refractory material; crystals of silicon carbide can be used as semiconductors