Normally we shoot for embedding elements that are at least 99% pure but we make exceptions in a few cases where this isn't practical. Clearly, even if it were possible nobody would want a sizeable sample of pure radon gas. At least we think nobody would want such a thing. Radon gas is responsible for over 20,000 lung cancer deaths in the U.S. alone where it concentrates in the basements of many homes built in regions where there's a lot of granite or shale.

No worries with this sample offered here however. The amount of radon is very small and trapped behind this much acrylic it is fully shielded from causing any harm. The radon comes from a precisely measured amount of thorium dioxide the decay chain of which yields some 0.00000000017 of a gram's worth of radon atoms at any one time. The weight being so slight it's difficult to get a visual of how much radon you're buying but it would probably take up the volume of a grain of sand... with the rest of the ampule being regular air and the powdered ThO2. All, of course, tidily presented in our beautifully finished 5cm Lucite acrylic cube!