Answer: Osmium

When people think of dense elements, they usually think of lead thanks to both its widespread use as a cheap weight and colloquialisms like “that’ll go over like a lead balloon” that allude to its heft. Among its companion elements on the periodic table, however, lead, with a density of 11.34 grams per cubic centimeter, isn’t even among the top 20 densest elements and just barely squeezes into the top 25 list.

In fact, the densest element on the periodic table is a brittle blueish-white transition metal in the platinum group called osmium. Osmium has a heavy-in-the-hand density of 22.59 grams per cubic centimeter (nearly twice the density of lead).

In addition to the distinction of being the most dense naturally occurring element, it also has the distinction of being the least abundant stable element in Earth’s crust. It occurs with a frequency of around 50 parts per trillion in the continental crust. By comparison other elements, like iron, are so abundant that we can give their measurements in much larger and easier to digest numbers—about 5 percent of the Earth’s crust is iron.