These tiny magnets are made of the same alloy of Neodymium, Iron, and Boron as our 12mm cube magnets.
These are small beads that string nicely on copper wire for the Curie Effect Heat Engine. They are also used in our Ring Launcher and Zip Rod projects.
They are plated in gold to seal the sensitive alloy from moisture. They are 3 millimeters in diameter, 2 millimeters high, and have a 1 millimeter hole in the center.