This rarely seen metal is most typically associated with nuclear pollution. Finding the strontium-90 isotope in the atmosphere around your neighborhood is bad news indeed and should be cause for immediate plans to relocate to your mother-in-law's for a while. But don't worry, that should only happen if you live near a malfunctioning nuclear power plant.

Strontium's other isotopes are considerably less harmful. In fact, one big use of it goes into toothpaste because it coats teeth in a microscopic film that protects against cavities. The piece here would be enough to seal a city's worth of its denizens' teeth. We really don't recommend chewing on it though.

Doubly rare is the sight of oxide-free strontium as the metal quickly oxidizes when in air or anything that has the merest whisper of oxygen in any form. Our lab-sourced samples come in ampules filled with argon to preserve the pristine surface of the metal. The ampules are then permanently embedded in these polished cubes in the highest grade of acrylic resin available: Lucite.