Some types of stone are harder than many metals. It takes a very hard material to drill efficiently through brick, concrete and stone-like granite. The Moh's scale of hardness ranks the hardness of material on a scale from 1 to 10. The lower the number, the softer the material. Only something that ranks even higher on the Moh's scale can scratch something that ranks higher. Diamond and tungsten carbide are two of the hardest known materials; they rank 10 and 9 on the Moh's scale, respectively. Tungsten carbide and diamond-tiped drill bits can easily cut through granite, some of the hardest stone on the Earth (6 hardness ranking).
Both diamond-tipped masonry drill bits and tungsten carbide masonry drill bits link with some steep prices. These drill bits are more expensive than almost every other type of drill bit available. Diamond-tipped bits, however, are several times more expensive than even tungsten carbide bits. They are the most expensive drill bits on the market. A tungsten carbide masonry drill bit can cost anywhere from a couple dollars to well over $20. Diamond-tipped drill bits are available also for as little as a few dollars apiece but can reach well over $100 apiece.
Diamond-tipped and tungsten carbide drill bits can retain their edge through an aggressive regular routine of drilling. The manufacturer designs them for replacement after they lose their edge. Never sharpen diamond-tipped drill bits. The diamond component of these bits is merely a thin layer applied to the surface of a quality steel drill bit. Sharpening these bits can remove the diamond coating. Manufacturers construct many tungsten carbide masonry bits with only a coating of tungsten carbide. Sharpening these drill bits also removes the tungsten carbide coating. Consumers have access to drill bits made of solid tungsten carbide. You can sharpen these bits.
Both types of masonry drill bits perform in much the same way. They both outperform drill bits made out of other materials like titanium in high-heat, high-speed applications. However, a well-maintained diamond-tipped masonry drill bit will always outlast and outperform a tungsten carbide drill bit. While titanium is one of the harder metals available, it only ranks a 6 on the Moh's scale of hardness. Titanium drill bits are inefficient for drilling through hard stone like granite.