<prompt> Which of the following materials can be routinely used to sharpen carbide instruments?Arkansas stoneSilicon carbideAluminium oxideDiamond  <response>: Diamond is the hardest available abrasive and is the most effective for cutting and shaping hard materials.It is the only material routinely capable of sharpening carbide as well as steel instruments.Ref: Sturdevants art and science of operative dentistry. 4th edition page 317 