Francium is a rare element that occurs naturally in the earth's crust. It has a half-life of 22 minutes. Since it decays so quickly, it is hard to acquire, making it the most expensive metal on Earth.

Californium is a rare and expensive element, with radioactive, dangerous and difficult handling situations. Each year, only a half-gram of Californium is produced, escalating its demand and prices.

Berkelium is a radioactive element and needs nuclear attention. Being the third most expensive element, it inspires the creation of other expensive, synthetic elements, such as Tennessine.

Plutonium is rare and is derived from uranium that costs $4,000 per gram. It’s one of the radioactive metals used to power space missions, including the Mars Curiosity Rover.

Neptunium encounters human interactions in nuclear facilities or scientific laboratories. This rare and valuable isotope is used for spacecraft, military applications, weapons applications and more.

Scandium occurs in very small amounts in nature. It has been labelled the 50th most abundant element on Earth, distributed widely in trace quantities in over 800 minerals.