Rare Earth Magnets come in various sizes, shapes, and grades.
Press Release Summary:

Original Press Release:
Bunting Offers New Rare Earth Magnets
NEWTON, KS - Bunting Magnetics Co. has expanded its line of high-energy Neodymium and Samarium Cobalt permanent magnets to include additional shapes, sizes, and grades, as well as Rare Earth holding assemblies. The Neo Assemblies come in concentric and two- and three-pole configurations and are corrosion resistant.
Neodymium Rare Earth magnets offer very high energy and holding power in compact sizes and light weights. Bunting Neodymium-Iron-Boron magnets are now stocked in six grades and dozens of standard sizes and shapes, including bar and plug shapes. The selection includes a heat-resistant grade plus corrosion-resistant nickel-plated Neodymium magnets.
Samarium Cobalt Rare Earth magnets are ideal for use in many high-energy and high-temperature applications. These magnets combine energy products that approach those of Neodymium grades with temperature stability similar to that of Alnico magnets.