The US Air Force is looking into making bombs out of anti-matter. I want a key ring with a speck of it!
One millionth of a gram of positrons contain as much energy as 37.8 kilograms (83 pounds) of TNT, according to Edwards' March speech. A simple calculation, then, shows that about 50-millionths of a gram could generate a blast equal to the explosion (roughly 4,000 pounds of TNT, according to the FBI) at the Alfred P. Murrah Federal Building in Oklahoma City in 1995.
UPDATE:Tom sez: Anti-matter is easier to come by than one might think. 22Sodium isotope naturally emits positrons and this property is used in many nuclear metrology applications (PET scans, positron annihilation spectroscopy, etc.). So a bit of isotope table salt might fit nicely in Mark's ring. Link to PDF file
