3/32" dia. shanks are the jeweler's preferred standard for burs and small rotary tools. They fit the adjustable chucks found on most flexshaft handpieces as well as 3/32" handpiece collets.
Cylinder Burs can be used like a flat file. They can remove large amounts of material quickly. Large cylinder burs are useful for grinding the insides of ring shanks to increase their size.
Diamond Burs/Points are made from steel that has diamond particles permanently bonded to the outside. They are ideal for carving glass, stone, ceramic, and metal. They must be used with water or another lubricant.