Osmium

Osmium is a rather rare and accordingly expensive element.
Thus it is of no real interest for macrostructural applications.

Interesting trivia:

• Osmium is the densest naturally occurring element (22.59 g/ccm). – See: Ultimate limits
• It's oxide is a (rather toxic) transparent liquid.
  Ruthenium (same group) and Rhenium (to the left) do that too. – See: Oddball compounds

Osmiums group members are:

• Ruthenium – also a rather rare and expensive element
• Iron – tremendously abundant much less noble
• The artificial element highly radioactive element Hassium (longest half live tine 110s)
  See: Artificial short lived elements