Tritium – $30 Million/kg

Naturally occurring tritium is very rare on earth. In fact, there are only trace elements of the product in our environment. Due to its important nature in our mechanical devices, scientists and production companies found ways to create the substance artificially, but it doesn’t come cheap.

One gram of Tritium costs $30,000, making it one of the most expensive substances on the planet. Still, Tritium is used in radioluminescent watches, self-illuminating key chains, and various tools as their energy source despite its expensive nature. If you’ve ever wondered why some items don’t need a battery to light up in the dark, now you know why.