Osmium

Osmium is a chemical element. It is element number 76 on the periodic table. Its symbol is Os.

There is not much osmium on earth. There is actually such a small amount that osmium is very expensive.

Osmium is a metal and it does not react very much, and such a metal is known as a "noble metal".

Osmium is the densest (heaviest for the same amount) element on the periodic table.

It was discovered in 1804 by Smithson Tennant in London, England. He found it together with Iridium in a bit of Platinum, which he had dissolved in Aqua regia.