Permanent magnets' Shapes 

Permanent magnets can be made in most any shape imaginable.  They can be made into round bars, rectangular bars, horseshoes, rings or donuts, disks, rectangles, multi-fingered rings, and other custom shapes.  Some are cast into a mold and require grinding to achieve final dimensions.  Others start as a powder which is pressed into a mold or pressure bonded or sintered.

Here are some of the common types available for performing your experiments.

This is a small disk NIB magnet, about 0.50" diameter, 0.125" thick.

This is a very small disk NIB magnet, about 3/16" diameter, 1/32" thick, used for magnetic earrings.

This is a larger disk NIB magnet, about 1" diameter, 0.25" thick.

This is a small donut or ring ceramic magnet, about 1.25" OD, 0.375" ID, 0.125" thick.

This is a large donut or ring ceramic magnet, about 2.75" OD, 1.125" ID, 0.50" thick.  These have a lot of pull!

This is a kidney shaped NIB magnet, about 7/8" by 0.50", 0.10" thick.

This is a trapezoidal shaped NIB magnet, about 1.25" by 0.75", 0.375" thick.  These are very powerful!

These are several marble magnets, each about 0.5" diameter.

This is a wand ceramic magnet.  They are quite strong, great for experimenting.

This is a real alnico cow magnet.

These are an assembled cow magnet.

This is an alnico horseshoe magnet.  Please note the keeper on the end of the magnet, which helps to prevent the magnet from becoming demagnetized.

This is a long, narrow alnico bar magnet.

This is a slightly flexible ceramic or ferrite disk magnet.  Not very strong, but not likely to chip, either.

This is a ferrite bar magnet.  Quite strong.

This is another ferrite bar magnet, actually, more like a block or brick!  On both of these ferrite magnets, you can see little chips missing along the edges.  This happens when they are allowed to come together quickly.

 This is a string of 100 spherical magnets that stick to each other.  These are a lot of fun to play with - just not good for small children.

Sintered Ndfeb Magnets: 

Alnico:

Smco:

Ferrite / Ceramic Magnets: