oh, this is neat! you can get little 10mm cubes of various metals: https://www.amazon.com/Vanadium-Metal-10mm-Density-99-95/dp/B071J61M2C
it'd be kind of neat to get a tungsten one actually. tungsten is remarkably dense, significantly more so than lead, slightly more even than gold. It's probably the densest metal we could reasonably expect to own a decent-sized sample of; rhenium, platinum, osmium, and iridium are all precious metals, and americium and uranium are radioactive.
also I find it amusing they seem to be claiming that these are monatomic. metals are not monatomic until you vaporize them and you don't want to be ingesting vaporized metals for quite a wide variety of reasons